For Exercises 13–18, a random sample is drawn from a normal population. Do the following:

  1. State the hypotheses and the rejection rule.
  2. Calculate . Draw a distribution and indicate the location of .
  3. Find the -value and indicate the -value in your distribution in (b).
  4. Compare the -value with level of significance . State the conclusion and interpretation.

Question 9.340

17. We are testing whether , and have a sample of size and a sample variance of .

9.6.17

(a) . Reject if the . (b)

image

(c) (d) Since the is not , we do not reject . There is insufficient evidence that the population standard deviation is less than 20.