Thirty randomly selected students took the calculus final. If the sample mean was 92 and the standard deviation was 9.4, construct a 99 percent confidence interval for the mean score of all students.
A) 87.29 < < 96.71 B) 87.77 < < 96.23 C) 89.08 < < 94.92 D) 87.27 < < 96.73
Question 2
To find the standard deviation of the diameter of wooden dowels, the manufacturer measures 19 randomly selected dowels and finds the standard deviation of the sample to be s = 0.16.
Find the 95 confidence interval for the population standard deviation .
A) 0.15 < < 0.21 B) 0.13 < < 0.22 C) 0.11 < < 0.25 D) 0.12 < < 0.24
