Question 142549
The School Committee members of a midsized New England city agreed that a strict 
discipline code has caused an increase in the number of student suspensions. The number of suspensions for September 1992 - February 1993 for a sample of the schools is provided below. {Data} 
The average number of suspensions for the previous year mean{X bar} = 130.5 and the Standard deviation {STDEV} was 158.2 
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(a) Set up the null and alternative hypothesis to test if the average number of suspensions has changed.
Ho: u = 130.5
H1: u is not equal to 130.5

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(b) Test your hypothesis with alpha = 0.05. 
Critical values for 2-tail test with alpha = 5%: z = +-1.96
Test statistic: z(195) = (195-130.5)/[158.2/sqrt(10)] = 1.2893...
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(c) Find the p value. 
p-value = 2*P(1.2893 < z < 10) = 0.1973
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(d) Display the data in an Excel Chart to see if it is reasonable to assume that the underlaying population distribution is normal. 
I'll leave that to you.
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(e) Based on the p value, what can you conclude about the average number of suspensions?
The p value is greater than 5% so fail to reject Ho. 
The average number of suspensions has not changed.
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Cheers,
Stan H.