Mikel  Okuneva

Mikel Okuneva

1596906000

Taking on T-Tests with SciPy

Ah T-Tests, one of the many ways to determine statistical significance. But what exactly are they? And how exactly does everything work?

T-Tests, otherwise known as a Student’s T-Test, are a simple way to compare averages between two groups to assess whether or not they are different from each other. They are frequently used when one either does not know the true population standard deviation, or if the sample size is small. This is all done assuming that the data is normally distributed.

There are two kinds of T-Tests, a one-tailed T-Test, and a two-tailed T-Test.

one-tailed T-Test is used to determine if the mean of one group is much higher than the other, or much lower, depending on which you select. Only one is selected for the test.

On the other hand, a two-tailed T-Test is used to see if mean of one group is higher or lower than the other group.

Image for post

Image for post

A One-Tailed(left) and a Two-Tailed(right) T-Test. Source: UCLA: Statistical Consulting Group

one group is higher or lower than the other group.

Image for post

A small cup of coffee

To start, you have to actually gain a basic understanding of your data. Once you do, you’ll know what questions to ask, and then determine your null and alternative hypothesis, 𝐻0 and 𝐻1 respectively.

For example, a company is trying to use a new process of brewing coffee that results in less acidity. What kind of test is used for this?

That’s right, a one-tailed T-Test! So, let’s say that the population mean of the new coffee, or 𝜇 (pronounced “mew”), is 4.4 ph. We will be estimating this using the sample mean, x̄ (x-bar).

First, we’re going to set 𝐻0 and 𝐻1. For our null hypothesis, we’re going to assume that there will be no difference in acidity, and for the alternative hypothesis we will state that the new coffee’s acidity will be lower than standard coffee.

In more mathematical terms:

𝐻0:𝜇=4.4

𝐻1:𝜇<4.4

Next, we need to determine the alpha value, 𝑎, so that we can compare it to the resulting P-Value and determine if our results are statistically significant.

Wait, what the heck are those?!

The alpha value is how much risk we’re willing to take when it comes to the probability of the experiment returning a false positive (we falsely reject the null hypothesis) or a false negative (we falsely fail to reject the null hypothesis). The lower 𝑎a is, the lower the chance of a false positive. However, if an alpha value is too low then you risk getting a false negative! Typically, 𝑎 is set to 0.05 or 0.01, 5% or 1% risk.

Simplified, the P-Value is the probability of seeing a sample statistic at least as extreme as the one observed assuming 𝐻0 is true.

A low P-Value indicates that it is unlikely that the results you obtained from your experiment happened by chance, while inversely a high P-Value suggests that it is likely that your results did happen due to natural variation.

For the coffee experiment, we’ll just set 𝑎 to 0.05.

Now we can begin our experiments! Or more accurately in this case, grab the example experiment data and check it out. Our coffee company only made 100 cups of coffee using this new method, so this is a pretty good sample size!

Note that that as the number of samples, 𝑛n, becomes larger, the resulting distribution of the mean will reach a more distinct bell curve shape! This applies no matter what the initial sample or population distribution actually was. This is called Central Limit Theorem, and you can read more about it here and here!

#statistics #t-test #taking

What is GEEK

Buddha Community

Taking on T-Tests with SciPy

Đặc biệt, bên cạnh một hệ thống tủ locker, các bộ khóa tủ là sự kết hợp hoàn hảo, hỗ trợ công tác bảo quản tư trang và lưu trữ hồ sơ quan trọng tại nơi công sở hiệu quả hơn.

#tủ_locker #tủ_sắt_locker #locker #tu_sat_locker #tu_locker #tủ_locker_sắt #tủ_nhân_viên #tu_locker_sat #tủ_locker_giá rẻ #tu_locker_gia_re #tủ_cá_nhân_locker #tủ_sắt_nhiều_ngăn #tủ_đựng_đồ_nhân_viên

Website: 

tủ locker

tu locker gia re

tủ cá nhân locker

tủ sắt nhiều ngăn

tủ đựng đồ nhân viên


 

tu locker

1635748246

Sự hiện diện của giải pháp Smart Locker, như một nâng tầm dịch vụ, sẽ giúp khách hàng chứa đựng tư trang trước khi thoải mái tận hưởng thời gian mua sắm.

#tủ_locker #tủ_sắt_locker   #locker #tu_sat_locker #tu_locker #tủ_locker_sắt #tủ_nhân_viên #tu_locker_sat #tủ_locker_giá rẻ #tu_locker_gia_re #tủ_cá_nhân_locker #tủ_sắt_nhiều_ngăn #tủ_đựng_đồ_nhân_viên

Website: 

locker

tủ sắt nhiều ngăn

tủ đựng đồ nhân viên

tủ locker

tủ sắt locker


 

Tủ iLocker

Tủ iLocker mang nhiều đặc điểm nổi bật, cùng các phương thức bảo mật khác nhau như Fingerprint, RFID, Face ID hoặc QR code được xem là giải pháp lưu trữ tối ưu của Smart Locker

#tủ_locker #tủ_sắt_locker   #locker #tu_sat_locker #tu_locker #tủ_locker_sắt #tủ_nhân_viên #tu_locker_sat #tủ_locker_giá rẻ #tu_locker_gia_re #tủ_cá_nhân_locker #tủ_sắt_nhiều_ngăn #tủ_đựng_đồ_nhân_viên

Website: 

tủ locker

tủ sắt locker

locker

tu sat locker

tu locker


 

cloek

Tủ locker ABS w600 khối gồm có 24 ngăn đều nhau, cánh sắt mở sử dụng khóa thông minh , tay nắm và có thêm tấm chia ngăn, trên mỗi cánh cửa được dập 1 bảng tên nhân viên và 1 lỗ thông gió

#tủ_locker #tủ_sắt_locker #locker #tu_sat_locker #tu_locker #tủ_locker_sắt #tủ_nhân_viên #tu_locker_sat #tủ_locker_giá rẻ #tu_locker_gia_re #tủ_cá_nhân_locker #tủ_sắt_nhiều_ngăn #tủ_đựng_đồ_nhân_viên

Website: 

ilocker

tủ sắt nhiều ngăn

tủ đựng đồ nhân viên

tủ locker

tủ sắt locker


 

Tủ locker

Tủ locker dòng W900 là sản phẩm có thể xếp chồng lên được 3 tầng cho 1 cột, có thể kết hợp nhiều cột tủ lại với nhau theo mong muốn (không giới hạn số lượng cột tủ)

#tủ_locker #tủ_sắt_locker #locker #tu_sat_locker #tu_locker #tủ_locker_sắt #tủ_nhân_viên #tu_locker_sat #tủ_locker_giá rẻ #tu_locker_gia_re #tủ_cá_nhân_locker #tủ_sắt_nhiều_ngăn #tủ_đựng_đồ_nhân_viên

Website: 

tủ locker

tủ locker giá rẻ

tu locker gia re

tủ cá nhân locker

tủ sắt nhiều ngăn