Is there evidence that the mean cost for student textbooks at the University of China is above $310?
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3. The director of admissions at the University of China is concerned about the high cost of textbooks for the students each semester. A sample of 20 students enrolled in the university indicates that X (bar) = $316.4 and s = $43.20. Answer the following questions in detail by using Excel.
a. Using the 0.10 level of significance, is there evidence that the population mean is above $310
b. What is your answer in (a) if s = $75 and the 0.05 level of significance is used?
c. What is your answer in (a) if X (bar) = $305.11 and s = $43.20?
d. Based on the information in part (a), what decision should the director make about the books used for the courses if the goal is to keep the cost below $300?
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This solution provides calculations for testing the hypothesis that the population mean is above $310 in plain text and in an attached Word document.
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3. The director of admissions at the University of China is concerned about the high cost of textbooks for the students each semester. A sample of 20 students enrolled in the university indicates that X (bar) = $316.4 and s = $43.20.
a. Using the 0.10 level of significance, is there evidence that the population mean is above $310?
Null Hypothesis: Mean= $310
Alternative Hypothesis: Mean> $310
Mean=M =$310.00
Standard deviation =s=$43.20
sample size=n=20
sx=standard error of mean=s/square root of n=9.6598= ( 43.2 /square root of 20)
Significance level=a (alpha) =0.1or10%
No of tails=1
This is a 1tailed test because we are testingM 1>M 2
Since sample size=20<30
and we are estimating the population standard deviation from sample standard deviation
we will use t distribution
sample mean=$316.40
t at the 0.1 level of significance and 19 degrees of freedom (=n-1) and1 tailed test=1.3277
Upper ...
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