A survey claims that 9 out of 10 doctors (i.e., 90%) recommend brand Z for their patients who have children. To test this claim against the alternative that the actual proportion of doctors who recommend brand Z is less than 90%, a random sample of 100 doctors results in 83 who indicate that they recommend brand Z.

Find the test statistic for this test.

a) What is the population proportion?

b) What is the sample proportion?

c) What is n?

d) Give the final test statistic.