A test of spelling ability is given to a random sample of 10 students before and after they completed a spelling course.The mean score before the course was 119.60 and after the course the mean score was 130.80.The standard deviation of the difference was 16.061.Based on this information,the critical value to assess the t-test statistic for a two-sided test at $\alpha$
=)05 is _____.
A)1.121
B)2.262
C)1.613
D)2.014
E)2.215

Question

Quizplus · Accepted Answer

The critical value for a two-sided t-test at $\alpha = 0.05$ with $n - 1 = 9$ degrees of freedom (since there are 10 students, and degrees of freedom $df = n - 1$) is found in the t-distribution table. For a two-sided test at $\alpha = 0.05$ and $df = 9$, the critical value is approximately 2.262.

A Test of Spelling Ability Is Given to a Random α\alphaα

A Test of Spelling Ability Is Given to a Random $\alpha$