Final Exam Review STAT 212

Transcription

1 Final Exam Review STAT 212 1/ A market researcher randomly selects 100 homeowners under 60 years of age and 200 homeowners over 60 years of age. What sampling technique was used? A. Systematic B. Convenience C. Stratified D. Simple Random E. Cluster 2/ A small computing center has found that the number of jobs submitted per day to its computers has a distribution that is approximately bell shaped, with a mean of 84 jobs and a standard deviation of 10. Where do you expect approximately 95% of the distribution to fall? A. Between 74 and 94 jobs per day B. Between 64 and 114 jobs per day C. Between 64 and 104 jobs per day D. Between 54 and 114 jobs per day 3/ The tread life of a particular brand of tire is a random variable best described by a normal distribution with a mean of 60,000 miles and a standard deviation of 2500 miles. What warranty should the company use if they want 96% of the tires to outlast the warranty? A. 55, 625 mi B. 62,500 mi C. 57,500 mi D. 64,375 mi 4/ The greater the power of the test the more likely the test will A. Reject Ho when H1 is false B. Reject H0 when H0 is false C. Fail to reject Ho when H1 is false D. Fail to reject Ho when H0 is false 5/ To reduce the type 2 error, which following statements are true: A. Increase type 1 error (alpha) B. Decrease sample size C. Increase sample size D. A and C E. A and B

2 6/ What is the probability of type 1 error A. Alpha B. Beta C. Delta D. Omega 7/ What is the probability of type 2 error A. Alpha B. Beta C. Delta D. Omega 8/ The probability of type 2 error (beta) is What is the power? A B C D / Data set A and B are dependent. Find the standard deviation of the differences ( S d) d = 45 d 2 = 649 A B A. 5.6 B. 8.9 C. 7.8 D / Determine the expected counts for each outcome N = 600 pi Expected Count A. 25,5,35,35 B. 154,28,211,207 C. 1500,300,2100,2100 D. 150,30,210,210

3 11/ Find the standardized test statistic, z 0 to test the hypothesis that p 1>p 2. Use alpha = The sample statistics listed below are from independent samples Sample statistics: n 1= 50, x 1 = 35 and n 2= 60, x 2 = 40 A B C D / Suppose you want to test the claim that u > Given a sample size of n = 51 and a level of significant of alpha = 0.01, when should you reject H 0 A. Reject H 0 if the test statistic is greater than 1.28 B. Reject H 0 if the test statistic is greater than C. Reject H 0 if the test statistic is greater than 2.39 D. Reject H 0 if the test statistic is greater than / Suppose you want to test the claim that u < Given a sample size of n = 51 and a level of significant of alpha = 0.01, when should you reject H 0 A. Reject H 0 if the test statistic is greater than 1.28 B. Reject H 0 if the test statistic is greater than C. Reject H 0 if the test statistic is less than D. Reject H 0 if the test statistic is less than / Calculating the chi-square test statistic to test the claim that the probabilities of winning are the same in the different positions. Use alpha = The results are based on 240 wins. Starting position number of wins A B C D

4 15/ Find the correlation coefficient for the given data X Y x = -5 y = 22 x 2 = 85 y 2 = 370 xy = -28 A. 0 B C D Using this information for question 16, 17, 18 and 19. The contingency table below shows the results of a random sample of 200 registered voters that was conducted to see whether their opinion on a bill are related to their party affiliation. Use alpha = 0.05 Party Opinion Approve Disapprove No Opnion Total Republication Democrat Independent Total / What is the hypothesis test to use? A. Chi-Square of Goodness Fit B. Chi-Square of Independent C. Anova D. Linear Regression 17/ Find the critical value A B C D / Find the probability of republication party and approval on the bill? 19/ Given the republication party, find the probability that number of people approve the bill?

5 An environmentalist wanted to test if the mean acidity of rain differed among Alaska, Florida and Texas. He randomly selected six rain dates at three of the locations and this is the following data for the acidity of rain collected Alaska Florida Texas n mean Variance Hint: S 2 x = / Determine what kind of hypothesis test? A. Chi-Square of Goodness Fit B. Chi-Square of Independent C. Anova D. Paired-t test 21/ Calculate the F 0 test statistic to test this claim at an alpha = 0.05 level of significant? A B C D / Many people think that a national lobby s successful fight against gun control registration is reflecting the will of a minority of Americans. A random sample of 4000 citizens yielded 2250 who are in favor of gun control registration. Estimate the true proportion using the 95 % confidence interval. A / B / C / D / / Two 6-sided dice are rolled. What is the probability that the sum of the two numbers on the dice will be 4? A. ½ B. 1/12 C. 1/9 D. 1 24/ A company wants to determine if its employees have any preference among 5 different health plans which it offers to them. A sample 200 employees provided the data below. Find the critical value to test the claim that the probabilities show no preference. Use alpha = 0.01 Plan

6 Employees A B C D / Increasing the sample size n will decrease the standard deviation A. True B. False 26/ Given the mean = 6 and standard deviation = 5. Assume the sampling normal distribution has n = 400, find the sample mean and standard deviation. A. Mean = 6, s= B. Mean = 6, s = 0.25 C. Mean = 0.015, s = D. Mean = 0.3, s = 0.25