SOLUTION: A group of 16 students are working together to study for a test. After the test, they calculated their mean score to be 91%. The entire class mean was 88% with a standard deviation

Question 562687: A group of 16 students are working together to study for a test. After the test, they calculated their mean score to be 91%. The entire class mean was 88% with a standard deviation of 4.43. Assuming you are working at 0.05 level of significance, what should you conclude? Choices are A. The students' average is significantly better than the whole class. B. The students' average is not significantly better than the whole class. C. We need the standard deviation of the student's grades. D. the z score is not the appropriate test to use.
I was calculating z scores, but I am stuck and becoming lost. Please help!
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A group of 16 students are working together to study for a test.
After the test, they calculated their mean score to be 91%.
The entire class mean was 88% with a standard deviation of 4.43.
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Assuming you are working at 0.05 level of significance, what should you conclude?
Ho: p = 0.88
Ha: p > 0.88
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t(0.91) = (0.91-0.88)/[0.0443/sqrt(16)] = 0.0111
p-score = P(t > 0.0111 when df = 15) = tcdf(0.0111,100,15) = 0.4956
Since the p-score is greater than 5% fail to reject Ho.
Choices are
A. The students' average is significantly better than the whole class.
B. The students' average is not significantly better than the whole class.
C. We need the standard deviation of the student's grades.
D. the z score is not the appropriate test to use.
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Ans: B
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Cheers,
Stan H.
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