A Sample of Students from an Introductory Business Course Were

A sample of students from an introductory business course were polled regarding the
number of hours they spent studying for the last exam. All students anonymously
submitted the number of hours on a 3 by 5 card. There were 24 individuals in the one
section of the course polled. The data was used to make inferences regarding the other
students taking the course. The data are shown below: $$\begin{array} { | c | c | c | c | c | c | c | c | c | c | c | c | } \hline 4.5 & 22 & 7 & 14.5 & 9 & 9 & 3.5 & 8 & 11 & 7.5 & 18 & 20 \\\hline 7.5 & 9 & 10.5 & 15 & 19 & 2.5 & 5 & 9 & 8.5 & 14 & 20 & 8 \\\hline\end{array}$$
A. Based on the sample results, find the 95% confidence interval.
b. Interpret the results.
c. Do you expect a 90% confidence interval to be wider or narrower and why?
d. A previous study of a large cross-section of students in this course showed that
students studies 12 hours per week. Are the results of this current study statistically
different than the assumption of 12 hours per week studying? Define the hypotheses and
compare the t-value to the critical t value, evaluating at α = 0.05.