A production line at a candy plant is designed to yield 2-lb boxes of assorted candies whose weights in fact follow a normal distribution with a mean of 33 ounces and a standard deviation of .30 ounce. A random sample of 36 boxes from the production of the most recent shift reveals a mean weight of 33.09 ounces. (Incidentally, if you think about it, this is an exception to the usual situation where the investigator hopes to reject the null hypothesis)

A- Describe the population being tested

B- Using the customary procedure, test the null hypothesis at the .05 level of significance.

C- Someone uses a one-tailed test, upper tail critical, because the sample mean of 33.09 exceeds the hypothesized population mean of 33. Any comment?

11-11

Supply the missing word(s) in the following statements: If the one observed sample mean can be viewed as a common or rare outcome under the hypothesis, H0 will be 500 .Otherwise, if the one observed sample mean can be viewed as a (c) outcome under the hypothesis, H0 will be (d) . The pair of z scores that separates common and rare outcomes is referred to as (e) zscores. Within the hypothesized sampling distribution, the proportion of area allocated to rare outcomes is referred to as the (f) and is symbolized by the Greek letter (g) . When based on the sampling distribution of z, the hypothesis test is referred to as a (h) test. This test is appropriate if the sample size is sufciently large to satisfy the (i) and if the (j) is known.

11.12According to theAmerican Psychological Association, member with a doctorate and a full-time reaching appointment earn on average $82,500 per year with a standard deviation of $6000. An investigator wishes to determine whether $82,500 also describes the mean salary for all female members with a doctorate and a full-time teaching appointment. Salaries are obtained for a random sample of 100 women from this population, and the mean salary equals $80,100(a) What form should H0 and H1 take if the investigator is concerned only about salary discrimination against female members? (b) If this hypothesis test supports the conclusion of salary discrimination against female members, a costly class-action suit will be initiated against American colleges and universities. Under these circumstances, do you recommend using the .05 or the .01 level of signicance? Why?

11.14 We must be concerned about four possible outcomes before conducting a hypothesis test. (a) Assuming that the test already has been conducted and the null hypothesis has been retained, about which of the four possible outcomes must we still be concerned? (b) Assuming that the test already has been conducted and the null hypothesis has been rejected, about which of the four possible outcomes must we still be concerned?

11.14a Using the .05 level of significance, an investigator retains H0. There is, he concludes, a probability of .95 that H0 is true. Comments?

11.14b In another study, an investigator rejects H0 at the.01 level of significance. There is, she concludes, a probability of .99 that H0 is false. Comments?