In: Statistics and Probability
How to do a dependent sample t-test and find t-crit
Procedure for dependent sample t - test and find t - crit:
Step 1:
Null Hypothesis H0 assumes the true mean difference ( ) is equal to zero.
The two - tailed Alternative Hypothesis (H1) assumes that is equal to zero.
The upper - tailed Alternative Hypothesis (H1) assumes that is greater than zero.
The lower - tailed Alternative Hypothesis (H1) assumes that is less than zero.
Step 2:
Calculate Sample mean () from the sample data of the differences.
Step 3:
Calculate Sample Standard Deviation (sd ) from the sample data of the differences.
Step 4:
Calculate Standard Error (SE):
Step 5:
Calculate the Test Statistic:
Step 6:
Calculate the probability of observing the test statistic under the null hypothesis. This value is obtained by comparing t to a t - distribution with n - 1 degrees of freedom.This is done by looking up the value in t Table.
Step 7:
If the calculated value of t is greater than critical value of t,
the difference is significant. Reject null hypothesis. Conclusion:
The data support the claim that the mean difference is not
zero.
If the calculated value of t is less than critical value of t, the difference is not significant. Fail to reject null hypothesis. Conclusion: The data do not support the claim that the mean difference is not zero.