In this article, I will present the 22 questions in fundamental statistics that you may encounter during interviews.

1, What is Hypothesis Testing?

Hypothesis Testing is a method of statistical inference. Based on data collected from a survey or an experiment, you calculate what is the probability (p-value) of observing the statistics from your data given the null hypothesis is true. Then you decide whether to reject the null hypothesis comparing p-value and significance level. It is widely used to test the existence of an effect.

2, What is the p-value?

P-value is the probability of observing the data if the null hypothesis is true. A smaller p-value means a higher chance of rejecting the null hypothesis.

3, What is the confidence level?

The** confidence level** in hypothesis testing is the probability of not rejecting the null hypothesis when the null hypothesis is true:

P(Not Rejecting H0|H0 is True) = 1 - P(Not Rejecting H0|H0 is False)

The default statistical power is set at 95%.

4, What is the confidence interval?

In contrast to point estimation, a confidence interval is an interval estimation of a parameter obtained through statistical inference. It is calculated by:

[point_estimation - cvsd, point_estimation + cvsd]

where cv is the critical value based on the sample distribution, and sd is the standard deviation of the sample.

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