Suppose that simple random samples of college freshman are selected from two uni

Question

Suppose that simple random samples of college freshman are selected from two universities - 40 students from school A and 35 students from school B.  On a standardized test, the sample from school A has an average score of 1000 with a standard deviation of 100.  The sample from school B has an average score of 950 with a standard deviation of 90.

a.)  (4 points)  Find a 90% confidence interval for the difference in mean test scores between the two schools. 

b.)  (4 points)  Based on the results of your confidence interval, can you conclude whether there is a difference between the two schools?  Explain your answer.

Explanation / Answer

a) alpha / 2 = 0.05 Z= 1.64

I: 1000 - 950 +/- 1.64 * SRQT ( 100^2 / 40 + 90^2 / 35 )

50 +/- 35.98

14.02 < MIU1 - MIU2 < 85.98

CONCLUISION :

THE MEANS ARE DIFFERENTS BECAUSE THE INTEVALDOES NOT CONTAIN "ZERO "

SO THE SAMPLE OF SCHOOL A IS GREATER THAN SAMPLE OF SCHOOL B

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