For Exercises 19–22, do the following:

  1. Check the normality conditions.
  2. State the hypotheses and the rejection rule for the -value method, using level of significance .
  3. Find .
  4. Find the -value.
  5. Compare the -value with level of significance . State the conclusion and the interpretation.

Question 9.287

21. Test whether the population proportion differs from 0.5. A random sample of size 900 yields 475 successes.

9.5.21

(a) We have and , so we may use the test for proportions. (b) Reject if the . (c) 1.67 (d) (e) Since the is not , we do not reject . There is insufficient evidence that the population proportion is not equal to 0.5.