Here is a sample of ACT scores (average of the Math, English, Social Science, and Natural Science scores) for students taking college freshman calculus:
|
24.00
|
28.00
|
27.75
|
27.00
|
24.25
|
23.50
|
26.25
|
|
24.00
|
25.00
|
30.00
|
23.25
|
26.25
|
21.50
|
26.00
|
|
28.00
|
24.50
|
22.50
|
28.25
|
21.25
|
19.75
|
|
a. Using an appropriate graph, see if it is plausible that the observations were selected from a normal distribution.
b. Calculate a two-sided 95% confidence interval for the population mean.
c. The university ACT average for entering fresh- men that year was about 21. Are the calculus students better than average, as measured by the ACT?