Reference no: EM133197015

Inferential Statistics Part

DQ1: Explain Type I error and give an example. Explain Type II error and give an example. What is the best way to reduce both kinds of error? Find a current scenario that has a Type I error and a Type II error. Is this scenario an example of an inverse relationship? Why or Why not?

DQ2: Review the term Significance Test in the "Statistics Visual Learner" media piece.
When a newspaper or magazine article reports the results of a study and draws a conclusion without also reporting whether the results are statistically significant, what are the possible reasons for doing so? How seriously should you take the conclusion offered in such a study? Discuss.

Assignment: Review Questions

Complete the following exercises from "Review Questions" located at the end of each chapter and put them into a Word document to submit to the instructor. Show all relevant work; use the equation editor in Microsoft Word when necessary.

Sampling Distribution of the Mean

Question 1: Given a sample size of 36, how large does the population standard deviation have to be in order for the standard error to be

a. 1 ?
b. 2 ?
c. 5 ?
d. 100 ?

Introduction to Hypothesis Testing: The Z Test

Question 2: Let's assume that, over the years, a paper and pencil test of anxiety yields a mean score of 35 for all incoming college freshmen. We wish to determine whether the scores of a random sample of 20 new freshmen, with a mean of 30 and a standard deviation of 10, can be viewed as coming from this population. Test at the .05 level of significance.

Hypothesis Testing

Question 3: Reread the problem described in Question 10.5 on page 191. Progress Check *10.5
According to the American Psychological Association, members with a doctorate and a full-time teaching appointment earn, on the average, $82,500 per year, with a standard deviation of
$6,000. An investigator wishes to determine whether $82,500 is also 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 significance? Why?

Question 4: How should a projected hypothesis test be modified if you're particularly concerned about

a. the type I error?
b. the type II error?

Question 5: - Estimation (Confidence Intervals)

Question 6: In Review Question 11.12 on page 218, instead of testing a hypothesis, you might prefer to construct a confidence interval for the mean weight of all 2-pound boxes of candy during a recent production shift.

Question 7: A production line at a candy plant is designed to yield 2-pound 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. Given a population standard deviation of .30 ounce and a sample mean weight of 33.09 ounces for a random sample of 36 candy boxes, construct a 95 percent confidence interval.
b. Interpret this interval, given the manufacturer's desire to produce boxes of candy that, on the average, exceed 32 ounces.

Attachment:- Inferential Statistics Assignment.rar