You are testing the claim that the mean GPA of night students is different from
ID: 3313012 • Letter: Y
Question
You are testing the claim that the mean GPA of night students is different from the mean GPA of day students. You sample 40 night students, and the sample mean GPA is 2.54 with a standard deviation of 0.42. You sample 20 day students, and the sample mean GPA is 2.73 with a standard deviation of 0.85. Test the claim using a 10% level of significance. Assume the population standard deviations are unequal and that GPAs are normally distributed. Give answer to at least 4 decimal places. What are the correct hypotheses? Based on the hypotheses, find the following: Test Statistic 0562 Critical Values- * (Just enter the positive CV)Explanation / Answer
Ans:
(Popolation standard deviations are unequal)
standard error for difference of means=sqrt((0.42^2/40)+(0.85^2/20))=0.20133
Test statistic:
t=(2.54-2.73)/0.20133=-0.9437
df=20-1=19 (we consider smaller of n1-1 or n2-1 as degree of freedom in case of unequal variances)
significance level=0.1
critical t values=tinv(0.1,19)=+/-1.7291