Z-test and T-test

Front

What is a Z-test?

Back

A Z-test is a statistical test used to determine whether there is a significant difference between the means of two groups when the population variance is known and the sample size is large (n > 30).

Front

What is a T-test?

Back

A T-test is a statistical test used to determine whether there is a significant difference between the means of two groups when the population variance is unknown and the sample size is small (n < 30).

Front

What are the null and alternate hypotheses?

Back

The null hypothesis (H0) states that there is no effect or no difference, while the alternate hypothesis (H1) states that there is an effect or a difference.

Front

What is the notation for the null hypothesis?

Back

H0

Front

How do you calculate the degree of freedom for a sample?

Back

DF = n - 1, where n is the sample size.

Front

What is the degree of freedom if the sample size is 20?

Back

19 (DF = 20 - 1).

Front

When should you use a Z-test?

Back

Use a Z-test when the population variance is known and the sample size is large (n > 30).

Front

When should you use a T-test?

Back

Use a T-test when the population variance is unknown and the sample size is small (n < 30).

Front

What is the significance level (alpha) in hypothesis testing?

Back

The significance level (alpha) is the probability of rejecting the null hypothesis when it is actually true, commonly set at 0.05.

Front

What does a p-value represent in hypothesis testing?

Back

A p-value represents the probability of obtaining test results at least as extreme as the observed results, assuming that the null hypothesis is true.