Graduate students in a statistics department recorded hours spent consulting on 21 different projects in a particular semester:
a. Just by looking at the data values, describe the general appearance of a display (such as histogram or stemplot) of the data.
b. Use software to produce a 95% confidence interval for mean hours spent on a consulting project for all semesters, assuming this semester was typical.
c. Report the center of your confidence interval (sample mean) and width of the interval.
d. Delete the value "148" from the data set and produce a 95% confidence interval.
e. Report the center and width of the new confidence interval.
f. Discuss the effect that an outlier can have on a confidence interval; is there an equally dramatic effect on its center and its width?