Question 424012: State College is evaluating a new English composition course for freshmen. A random sample of n=25 freshmen is obtained and the students are placed in the course during their first semester. One year later, a writing sample is obtained for each student and the writing samples are graded using a standardized evaluation technique. The average score for the sample is M=76. For the general population of college students, writing scores form a normal distribution with a mean of m=70.
a. If the writing scores for the population have a standard deviation of σ=20, does the sample provide enough evidence to conclude that the new composition course has a significant effect? Assume a two- tailed test with α=.05.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! State College is evaluating a new English composition course for freshmen.
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A random sample of n=25 freshmen is obtained and the students are placed in the course during their first semester. One year later, a writing sample is obtained for each student and the writing samples are graded using a standardized evaluation technique.
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The average score for the sample is M=76. For the general population of college students, writing scores form a normal distribution with a mean of m=70.
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a. If the writing scores for the population have a standard deviation of σ=20, does the sample provide enough evidence to conclude that the new composition course has a significant effect? Assume a two- tailed test with α=.05.
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Ho: u = 70
Ha: u > 70
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Note: You are running sample results for a mean against population
results for a mean. That is not a 2-tail test; it is a right-
tail test.
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I ran a T-test on the data and got the following:
test statistic: t = 1.5
p-value = 0.0733
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Conclusion: Since the p-value is greater than 5%, fail to
reject Ho.
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Cheers,
Stan H.
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