Anscombe’s Quartet — An Importance of Data Visualization

Usually people believe “the numerical calculations are exact, but graphs are rough” even though it’s completely wrong. Even I was not right about it before learning data analytics.

If you are new in the data science or its sub fields, believe me this is the first step towards the understanding of the importance of Data Visualization along with the statistics result.

Anscombe’s Quartet is the modal example to demonstrate the importance of data visualization which was developed by the statistician Francis Anscombe in 1973 to signify both the importance of plotting data before analyzing it with statistical properties. It comprises of four data-set and each data-set consists of eleven (x,y) points. The basic thing to analyze about these data-sets is that they all share the same descriptive statistics(mean, variance, standard deviation etc) but different graphical representation. Each graph plot shows the different behavior irrespective of statistical analysis.

Image for post

Four Data-sets

Apply the statistical formula on the above data-set,

Average Value of x = 9

Average Value of y = 7.50

Variance of x = 11

Variance of y =4.12

Correlation Coefficient = 0.816

Linear Regression Equation : y = 0.5 x + 3


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Anscombe’s Quartet — An Importance of Data Visualization

React Native Bridge for AppAuth

React Native App Auth

React native bridge for AppAuth - an SDK for communicating with OAuth2 providers 

This versions supports react-native@0.63+. The last pre-0.63 compatible version is v5.1.3.

React Native bridge for AppAuth-iOS and AppAuth-Android SDKS for communicating with OAuth 2.0 and OpenID Connect providers.

This library should support any OAuth provider that implements the OAuth2 spec.

We only support the Authorization Code Flow.

Why you may want to use this library

AppAuth is a mature OAuth client implementation that follows the best practices set out in RFC 8252 - OAuth 2.0 for Native Apps including using SFAuthenticationSession and SFSafariViewController on iOS, and Custom Tabs on Android. WebViews are explicitly not supported due to the security and usability reasons explained in Section 8.12 of RFC 8252.

AppAuth also supports the PKCE ("Pixy") extension to OAuth which was created to secure authorization codes in public clients when custom URI scheme redirects are used.

To learn more, read this short introduction to OAuth and PKCE on the Formidable blog.

Supported methods

See Usage for example configurations, and the included Example application for a working sample.


This is the main function to use for authentication. Invoking this function will do the whole login flow and returns the access token, refresh token and access token expiry date when successful, or it throws an error when not successful.

import { authorize } from 'react-native-app-auth';

const config = {
  issuer: '<YOUR_ISSUER_URL>',
  clientId: '<YOUR_CLIENT_ID>',
  redirectUrl: '<YOUR_REDIRECT_URL>',
  scopes: ['<YOUR_SCOPES_ARRAY>'],

const result = await authorize(config);


ANDROID This will prefetch the authorization service configuration. Invoking this function is optional and will speed up calls to authorize. This is only supported on Android.

import { prefetchConfiguration } from 'react-native-app-auth';

const config = {
  warmAndPrefetchChrome: true,
  issuer: '<YOUR_ISSUER_URL>',
  clientId: '<YOUR_CLIENT_ID>',
  redirectUrl: '<YOUR_REDIRECT_URL>',
  scopes: ['<YOUR_SCOPES_ARRAY>'],



This is your configuration object for the client. The config is passed into each of the methods with optional overrides.

  • issuer - (string) base URI of the authentication server. If no serviceConfiguration (below) is provided, issuer is a mandatory field, so that the configuration can be fetched from the issuer's OIDC discovery endpoint.
  • serviceConfiguration - (object) you may manually configure token exchange endpoints in cases where the issuer does not support the OIDC discovery protocol, or simply to avoid an additional round trip to fetch the configuration. If no issuer (above) is provided, the service configuration is mandatory.
    • authorizationEndpoint - (string) REQUIRED fully formed url to the OAuth authorization endpoint
    • tokenEndpoint - (string) REQUIRED fully formed url to the OAuth token exchange endpoint
    • revocationEndpoint - (string) fully formed url to the OAuth token revocation endpoint. If you want to be able to revoke a token and no issuer is specified, this field is mandatory.
    • registrationEndpoint - (string) fully formed url to your OAuth/OpenID Connect registration endpoint. Only necessary for servers that require client registration.
    • endSessionEndpoint - (string) fully formed url to your OpenID Connect end session endpoint. If you want to be able to end a user's session and no issuer is specified, this field is mandatory.
  • clientId - (string) REQUIRED your client id on the auth server
  • clientSecret - (string) client secret to pass to token exchange requests. :warning: Read more about client secrets
  • redirectUrl - (string) REQUIRED the url that links back to your app with the auth code
  • scopes - (array<string>) the scopes for your token, e.g. ['email', 'offline_access'].
  • additionalParameters - (object) additional parameters that will be passed in the authorization request. Must be string values! E.g. setting additionalParameters: { hello: 'world', foo: 'bar' } would add hello=world&foo=bar to the authorization request.
  • clientAuthMethod - (string) ANDROID Client Authentication Method. Can be either basic (default) for Basic Authentication or post for HTTP POST body Authentication
  • dangerouslyAllowInsecureHttpRequests - (boolean) ANDROID whether to allow requests over plain HTTP or with self-signed SSL certificates. :warning: Can be useful for testing against local server, should not be used in production. This setting has no effect on iOS; to enable insecure HTTP requests, add a NSExceptionAllowsInsecureHTTPLoads exception to your App Transport Security settings.
  • customHeaders - (object) ANDROID you can specify custom headers to pass during authorize request and/or token request.
    • authorize - ({ [key: string]: value }) headers to be passed during authorization request.
    • token - ({ [key: string]: value }) headers to be passed during token retrieval request.
    • register - ({ [key: string]: value }) headers to be passed during registration request.
  • additionalHeaders - ({ [key: string]: value }) IOS you can specify additional headers to be passed for all authorize, refresh, and register requests.
  • useNonce - (boolean) (default: true) optionally allows not sending the nonce parameter, to support non-compliant providers
  • usePKCE - (boolean) (default: true) optionally allows not sending the code_challenge parameter and skipping PKCE code verification, to support non-compliant providers.
  • skipCodeExchange - (boolean) (default: false) just return the authorization response, instead of automatically exchanging the authorization code. This is useful if this exchange needs to be done manually (not client-side)
  • connectionTimeoutSeconds - (number) configure the request timeout interval in seconds. This must be a positive number. The default values are 60 seconds on iOS and 15 seconds on Android.


This is the result from the auth server:

  • accessToken - (string) the access token
  • accessTokenExpirationDate - (string) the token expiration date
  • authorizeAdditionalParameters - (Object) additional url parameters from the authorizationEndpoint response.
  • tokenAdditionalParameters - (Object) additional url parameters from the tokenEndpoint response.
  • idToken - (string) the id token
  • refreshToken - (string) the refresh token
  • tokenType - (string) the token type, e.g. Bearer
  • scopes - ([string]) the scopes the user has agreed to be granted
  • authorizationCode - (string) the authorization code (only if skipCodeExchange=true)
  • codeVerifier - (string) the codeVerifier value used for the PKCE exchange (only if both skipCodeExchange=true and usePKCE=true)


This method will refresh the accessToken using the refreshToken. Some auth providers will also give you a new refreshToken

import { refresh } from 'react-native-app-auth';

const config = {
  issuer: '<YOUR_ISSUER_URL>',
  clientId: '<YOUR_CLIENT_ID>',
  redirectUrl: '<YOUR_REDIRECT_URL>',
  scopes: ['<YOUR_SCOPES_ARRAY>'],

const result = await refresh(config, {
  refreshToken: `<REFRESH_TOKEN>`,


This method will revoke a token. The tokenToRevoke can be either an accessToken or a refreshToken

import { revoke } from 'react-native-app-auth';

const config = {
  issuer: '<YOUR_ISSUER_URL>',
  clientId: '<YOUR_CLIENT_ID>',
  redirectUrl: '<YOUR_REDIRECT_URL>',
  scopes: ['<YOUR_SCOPES_ARRAY>'],

const result = await revoke(config, {
  tokenToRevoke: `<TOKEN_TO_REVOKE>`,
  includeBasicAuth: true,
  sendClientId: true,


This method will logout a user, as per the OpenID Connect RP Initiated Logout specification. It requires an idToken, obtained after successfully authenticating with OpenID Connect, and a URL to redirect back after the logout has been performed.

import { logout } from 'react-native-app-auth';

const config = {
  issuer: '<YOUR_ISSUER_URL>',

const result = await logout(config, {
  idToken: '<ID_TOKEN>',
  postLogoutRedirectUrl: '<POST_LOGOUT_URL>',


This will perform dynamic client registration on the given provider. If the provider supports dynamic client registration, it will generate a clientId for you to use in subsequent calls to this library.

import { register } from 'react-native-app-auth';

const registerConfig = {
  issuer: '<YOUR_ISSUER_URL>',

const registerResult = await register(registerConfig);


  • issuer - (string) same as in authorization config
  • serviceConfiguration - (object) same as in authorization config
  • redirectUrls - (array<string>) REQUIRED specifies all of the redirect urls that your client will use for authentication
  • responseTypes - (array<string>) an array that specifies which OAuth 2.0 response types your client will use. The default value is ['code']
  • grantTypes - (array<string>) an array that specifies which OAuth 2.0 grant types your client will use. The default value is ['authorization_code']
  • subjectType - (string) requests a specific subject type for your client
  • tokenEndpointAuthMethod (string) specifies which clientAuthMethod your client will use for authentication. The default value is 'client_secret_basic'
  • additionalParameters - (object) additional parameters that will be passed in the registration request. Must be string values! E.g. setting additionalParameters: { hello: 'world', foo: 'bar' } would add hello=world&foo=bar to the authorization request.
  • dangerouslyAllowInsecureHttpRequests - (boolean) ANDROID same as in authorization config
  • customHeaders - (object) ANDROID same as in authorization config
  • connectionTimeoutSeconds - (number) configure the request timeout interval in seconds. This must be a positive number. The default values are 60 seconds on iOS and 15 seconds on Android.


This is the result from the auth server

  • clientId - (string) the assigned client id
  • clientIdIssuedAt - (string) OPTIONAL date string of when the client id was issued
  • clientSecret - (string) OPTIONAL the assigned client secret
  • clientSecretExpiresAt - (string) date string of when the client secret expires, which will be provided if clientSecret is provided. If new Date(clientSecretExpiresAt).getTime() === 0, then the secret never expires
  • registrationClientUri - (string) OPTIONAL uri that can be used to perform subsequent operations on the registration
  • registrationAccessToken - (string) token that can be used at the endpoint given by registrationClientUri to perform subsequent operations on the registration. Will be provided if registrationClientUri is provided

Getting started

npm install react-native-app-auth --save


iOS Setup

To setup the iOS project, you need to perform three steps:

  1. Install native dependencies
  2. Register redirect URL scheme
  3. Define openURL callback in AppDelegate

Install native dependencies

This library depends on the native AppAuth-ios project. To keep the React Native library agnostic of your dependency management method, the native libraries are not distributed as part of the bridge.

AppAuth supports three options for dependency management.

  1. CocoaPods
cd ios
pod install

2.   Carthage

With Carthage, add the following line to your Cartfile:

github "openid/AppAuth-iOS" "master"

Then run carthage update --platform iOS.

Drag and drop AppAuth.framework from ios/Carthage/Build/iOS under Frameworks in Xcode.

Add a copy files build step for AppAuth.framework: open Build Phases on Xcode, add a new "Copy Files" phase, choose "Frameworks" as destination, add AppAuth.framework and ensure "Code Sign on Copy" is checked.

3.   Static Library

You can also use AppAuth-iOS as a static library. This requires linking the library and your project and including the headers. Suggested configuration:

  1. Create an XCode Workspace.
  2. Add AppAuth.xcodeproj to your Workspace.
  3. Include libAppAuth as a linked library for your target (in the "General -> Linked Framework and Libraries" section of your target).
  4. Add AppAuth-iOS/Source to your search paths of your target ("Build Settings -> "Header Search Paths").

Register redirect URL scheme

If you intend to support iOS 10 and older, you need to define the supported redirect URL schemes in your Info.plist as follows:

  • CFBundleURLName is any globally unique string. A common practice is to use your app identifier.
  • CFBundleURLSchemes is an array of URL schemes your app needs to handle. The scheme is the beginning of your OAuth Redirect URL, up to the scheme separator (:) character. E.g. if your redirect uri is com.myapp://oauth, then the url scheme will is com.myapp.

Define openURL callback in AppDelegate

You need to retain the auth session, in order to continue the authorization flow from the redirect. Follow these steps:

RNAppAuth will call on the given app's delegate via [UIApplication sharedApplication].delegate. Furthermore, RNAppAuth expects the delegate instance to conform to the protocol RNAppAuthAuthorizationFlowManager. Make AppDelegate conform to RNAppAuthAuthorizationFlowManager with the following changes to AppDelegate.h:

+ #import "RNAppAuthAuthorizationFlowManager.h"

- @interface AppDelegate : UIResponder <UIApplicationDelegate, RCTBridgeDelegate>
+ @interface AppDelegate : UIResponder <UIApplicationDelegate, RCTBridgeDelegate, RNAppAuthAuthorizationFlowManager>

+ @property(nonatomic, weak)id<RNAppAuthAuthorizationFlowManagerDelegate>authorizationFlowManagerDelegate;

Add the following code to AppDelegate.m (to support iOS <= 10 and React Navigation deep linking)

+ - (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary<NSString *, id> *) options {
+  if ([self.authorizationFlowManagerDelegate resumeExternalUserAgentFlowWithURL:url]) {
+    return YES;
+  }
+  return [RCTLinkingManager application:app openURL:url options:options];
+ }

If you want to support universal links, add the following to AppDelegate.m under continueUserActivity

+ if ([userActivity.activityType isEqualToString:NSUserActivityTypeBrowsingWeb]) {
+   if (self.authorizationFlowManagerDelegate) {
+     BOOL resumableAuth = [self.authorizationFlowManagerDelegate resumeExternalUserAgentFlowWithURL:userActivity.webpageURL];
+     if (resumableAuth) {
+       return YES;
+     }
+   }
+ }

Integration of the library with a Swift iOS project

The approach mentioned should work with Swift. In this case one should make AppDelegate conform to RNAppAuthAuthorizationFlowManager. Note that this is not tested/guaranteed by the maintainers.


  1. swift-Bridging-Header.h should include a reference to #import "RNAppAuthAuthorizationFlowManager.h, like so:
#import <React/RCTBundleURLProvider.h>
#import <React/RCTRootView.h>
#import <React/RCTBridgeDelegate.h>
#import <React/RCTBridge.h>
#import "RNAppAuthAuthorizationFlowManager.h" // <-- Add this header
#import <FlipperKit/FlipperClient.h>
// etc...

2.   AppDelegate.swift should implement the RNAppAuthorizationFlowManager protocol and have a handler for url deep linking. The result should look something like this:

class AppDelegate: UIApplicationDelegate, RNAppAuthAuthorizationFlowManager { //<-- note the additional RNAppAuthAuthorizationFlowManager protocol
  public weak var authorizationFlowManagerDelegate: RNAppAuthAuthorizationFlowManagerDelegate? // <-- this property is required by the protocol
  //"open url" delegate function for managing deep linking needs to call the resumeExternalUserAgentFlowWithURL method
  func application(
      _ app: UIApplication,
      open url: URL,
      options: [UIApplicationOpenURLOptionsKey: Any] = [:]) -> Bool {
      return authorizationFlowManagerDelegate?.resumeExternalUserAgentFlowWithURL(with: url) ?? false

Android Setup

Note: for RN >= 0.57, you will get a warning about compile being obsolete. To get rid of this warning, use patch-package to replace compile with implementation as in this PR - we're not deploying this right now, because it would break the build for RN < 57.

To setup the Android project, you need to add redirect scheme manifest placeholder:

To capture the authorization redirect, add the following property to the defaultConfig in android/app/build.gradle:

android {
  defaultConfig {
    manifestPlaceholders = [
      appAuthRedirectScheme: 'io.identityserver.demo'

The scheme is the beginning of your OAuth Redirect URL, up to the scheme separator (:) character. E.g. if your redirect uri is com.myapp://oauth, then the url scheme will is com.myapp. The scheme must be in lowercase.

NOTE: When integrating with React Navigation deep linking, be sure to make this scheme (and the scheme in the config's redirectUrl) unique from the scheme defined in the deep linking intent-filter. E.g. if the scheme in your intent-filter is set to com.myapp, then update the above scheme/redirectUrl to be com.myapp.auth as seen here.


import { authorize } from 'react-native-app-auth';

// base config
const config = {
  issuer: '<YOUR_ISSUER_URL>',
  clientId: '<YOUR_CLIENT_ID>',
  redirectUrl: '<YOUR_REDIRECT_URL>',
  scopes: ['<YOUR_SCOPE_ARRAY>'],

// use the client to make the auth request and receive the authState
try {
  const result = await authorize(config);
  // result includes accessToken, accessTokenExpirationDate and refreshToken
} catch (error) {

Error messages

Values are in the code field of the rejected Error object.

  • OAuth Authorization error codes
  • OAuth Access Token error codes
  • OpendID Connect Registration error codes
  • service_configuration_fetch_error - could not fetch the service configuration
  • authentication_failed - user authentication failed
  • token_refresh_failed - could not exchange the refresh token for a new JWT
  • registration_failed - could not register
  • browser_not_found (Android only) - no suitable browser installed

Note about client secrets

Some authentication providers, including examples cited below, require you to provide a client secret. The authors of the AppAuth library

strongly recommend you avoid using static client secrets in your native applications whenever possible. Client secrets derived via a dynamic client registration are safe to use, but static client secrets can be easily extracted from your apps and allow others to impersonate your app and steal user data. If client secrets must be used by the OAuth2 provider you are integrating with, we strongly recommend performing the code exchange step on your backend, where the client secret can be kept hidden.

Having said this, in some cases using client secrets is unavoidable. In these cases, a clientSecret parameter can be provided to authorize/refresh calls when performing a token request.

Token Storage

Recommendations on secure token storage can be found here.

Maintenance Status

Active: Formidable is actively working on this project, and we expect to continue for work for the foreseeable future. Bug reports, feature requests and pull requests are welcome.

Tested OpenID providers

These providers are OpenID compliant, which means you can use autodiscovery.

Tested OAuth2 providers

These providers implement the OAuth2 spec, but are not OpenID providers, which means you must configure the authorization and token endpoints yourself.

Download Details:
Author: FormidableLabs
Source Code:
License: MIT License

#react  #reactnative  #mobileapp #javascript #java 

Siphiwe  Nair

Siphiwe Nair


Your Data Architecture: Simple Best Practices for Your Data Strategy

If you accumulate data on which you base your decision-making as an organization, you should probably think about your data architecture and possible best practices.

If you accumulate data on which you base your decision-making as an organization, you most probably need to think about your data architecture and consider possible best practices. Gaining a competitive edge, remaining customer-centric to the greatest extent possible, and streamlining processes to get on-the-button outcomes can all be traced back to an organization’s capacity to build a future-ready data architecture.

In what follows, we offer a short overview of the overarching capabilities of data architecture. These include user-centricity, elasticity, robustness, and the capacity to ensure the seamless flow of data at all times. Added to these are automation enablement, plus security and data governance considerations. These points from our checklist for what we perceive to be an anticipatory analytics ecosystem.

#big data #data science #big data analytics #data analysis #data architecture #data transformation #data platform #data strategy #cloud data platform #data acquisition

Sid  Schuppe

Sid Schuppe


How To Blend Data in Google Data Studio For Better Data Analysis

Using data to inform decisions is essential to product management, or anything really. And thankfully, we aren’t short of it. Any online application generates an abundance of data and it’s up to us to collect it and then make sense of it.

Google Data Studio helps us understand the meaning behind data, enabling us to build beautiful visualizations and dashboards that transform data into stories. If it wasn’t already, data literacy is as much a fundamental skill as learning to read or write. Or it certainly will be.

Nothing is more powerful than data democracy, where anyone in your organization can regularly make decisions informed with data. As part of enabling this, we need to be able to visualize data in a way that brings it to life and makes it more accessible. I’ve recently been learning how to do this and wanted to share some of the cool ways you can do this in Google Data Studio.

#google-data-studio #blending-data #dashboard #data-visualization #creating-visualizations #how-to-visualize-data #data-analysis #data-visualisation

Gerhard  Brink

Gerhard Brink


Getting Started With Data Lakes

Frameworks for Efficient Enterprise Analytics

The opportunities big data offers also come with very real challenges that many organizations are facing today. Often, it’s finding the most cost-effective, scalable way to store and process boundless volumes of data in multiple formats that come from a growing number of sources. Then organizations need the analytical capabilities and flexibility to turn this data into insights that can meet their specific business objectives.

This Refcard dives into how a data lake helps tackle these challenges at both ends — from its enhanced architecture that’s designed for efficient data ingestion, storage, and management to its advanced analytics functionality and performance flexibility. You’ll also explore key benefits and common use cases.


As technology continues to evolve with new data sources, such as IoT sensors and social media churning out large volumes of data, there has never been a better time to discuss the possibilities and challenges of managing such data for varying analytical insights. In this Refcard, we dig deep into how data lakes solve the problem of storing and processing enormous amounts of data. While doing so, we also explore the benefits of data lakes, their use cases, and how they differ from data warehouses (DWHs).

This is a preview of the Getting Started With Data Lakes Refcard. To read the entire Refcard, please download the PDF from the link above.

#big data #data analytics #data analysis #business analytics #data warehouse #data storage #data lake #data lake architecture #data lake governance #data lake management

Vern  Greenholt

Vern Greenholt


Importance of Data Visualization — Anscombe’s Quartet Way.

Anscombe’s quartet comprises four data sets that have nearly identical simple descriptive statistics, yet have very different distributions and appear very different when graphed.

— Wikipedia

**Anscombe’s Quartet **can be defined as a group of four data sets which are nearly identical in simple descriptive statistics, but there are some peculiarities in the dataset that **fools the regression model **if built. They have very different distributions and **appear differently **when plotted on scatter plots.

It was constructed in 1973 by statistician Francis Anscombe to illustrate the **importance **of **plotting the graphs **before analyzing and model building, and the effect of other observations on statistical properties.There are these four data set plots which have nearly same statistical observations, which provides same statistical information that involves variance, and **mean **of all x,y points in all four datasets.

This tells us about the importance of visualising the data before applying various algorithms out there to build models out of them which suggests that the data features must be plotted in order to see the distribution of the samples that can help you identify the various anomalies present in the data like outliers, diversity of the data, linear separability of the data, etc. Also, the Linear Regression can be only be considered a fit for the **data with linear relationships **and is incapable of handling any other kind of datasets. These four plots can be defined as follows:

Image for post

The statistical information for all these four datasets are approximately similar and can be computed as follows:

Image for post

When these models are plotted on a scatter plot, all datasets generates a different kind of plot that is not interpretable by any regression algorithm which is fooled by these peculiarities and can be seen as follows:

Image for post

The four datasets can be described as:

  1. **Dataset 1: **this **fits **the linear regression model pretty well.
  2. Dataset 2: this **could not fit **linear regression model on the data quite well as the data is non-linear.
  3. **Dataset 3: **shows the **outliers **involved in the dataset which **cannot be handled **by linear regression model
  4. **Dataset 4: **shows the **outliers **involved in the dataset which **cannot be handled **by linear regression model

#data-science #machine-learning #data-visualization #linear-regression #exploratory-data-analysis #data analysisa