Comparing two population means

Assignment Help Engineering Mathematics

Reference no: EM13823621

Question 1: When comparing two population means with an unknown standard deviation you use a t test and you use N-2 degrees of freedom.

A. True

B. False

Question 2: Pretend you want to determine whether the mean weekly sales of soup are the same when the soup is the featured item and when it is a normal item on the menu. When it is the featured item the sample mean is 66 and the population standard deviation is 3 with a sample size of 23. When it is a normal item the sample mean is 53 with a population standard deviation of 4 and a sample size of 7. Given this information we could use a t test for two independent means.

A. True

B. False

Question 3: The alternative hypothesis can be proven if the alternative hypothesis is rejected.

A. True

B. False

Question 4: You want the determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 50 and a population standard deviation 5 and a sample size of 100. Machine 2 has a sample mean of 52 and a population standard deviation of 6 with a sample size of 36. With an alpha of .10 can we claim that there is a difference between the output of the two machines. Which of the following statements are true?

A. We will reject the null hypothesis and prove there is a difference between the 2 populations

B. We will not reject the null hypothesis and thus we can't prove there is difference between the 2 populations

C. The critical values you will use are 1.96 and -1.96

D. B and C are correct

E. None of the above are correct

Question 5: You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 50 and a population standard deviation 5 and a sample size of 25. Machine 2 has a sample mean of 52 and a population standard deviation of 6 with a sample size of 12. We have an alpha of .01. Which of the following statements is true.

A. We can use 2.58 and -2.58 (or 2.57 and -2.57) as our critical values

B. We will use a Z test

C. We use 1.28 and -1.28 (or 1.27 and -1.27) as our critical values

D. A and B are correct

E. None of the above are correct

Question 6: You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 500 and a population standard deviation 6 and a sample size of 18. Machine 2 has a sample mean of 500.5 and a population standard deviation of 2 with a sample size of 2. With an alpha of .05 can we claim that there is a difference between the output of the two machines. Which of the following statements are true?

A. We will reject the null hypothesis and prove there is a difference between the 2 populations

B. We will not reject the null hypothesis and thus we can't prove there is difference between the 2 populations

C. The critical values you will use are 1.96 and -1.96

D. B and C are correct

E. None of the above are correct

Question 7: You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 5 and a population standard deviation 2 and a sample size of 4. Machine 2 has a sample mean of 10 and a population standard deviation of 2 with a sample size of 64. With an alpha of .01 can we claim that there is a difference between the output of the two machines. Which of the following statements are true?

A. We will reject the null hypothesis and prove there is a difference between the 2 populations

B. We will not reject the null hypothesis and thus we can't prove there is difference between the 2 populations

C. The critical values you will use are 1.96 and -1.96

D. A and C are correct

E. B and C are correct

Question 8: You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 15.1 and a population standard deviation 5 and a sample size of 12.5. Machine 2 has a sample mean of 14.9 and a population standard deviation of 6 with a sample size of 12. With an alpha of .01 can we claim that there is a difference between the output of the two machines. Which of the following statements are true?

A. We will not reject the null hypothesis

B. The resulting test statistic will be less than 1

C. The critical values you will use are 1.96 and -1.96

D. A and B are correct

E. A, B, and C are correct

Question 9: The null hypothesis can be proven if it is not rejected.

A. True

B. False
Question 10: Pretend you are asked to test the claim that the true mean weight of gold bars in the safe is less than 15 ounces. You will have a/an...

A. lower tail test

B. upper tail test

C. two tail test

D. half tail test

E. four tail test

Question 11: Pretend you are asked to test the claim that the true mean weight of chocolate bars manufactured in a factory is more than 3 ounces. You will have a/an...

A. lower tail test

B. upper tail test

C. an alternative hypothesis that states the population mean is less than 3

D. A and C

E. B and C

Question 12: Your population mean used to be 7.1. The population standard deviation is 1.5. The sample size is 81. The sample mean is 4.2. .05 is your level of significance. The null hypothesis is that the population mean is = to 7.1, use your sample data to test this claim. If you use this information, you will reject the null hypothesis that the population mean is = 7.1.

A. True

B. False

Question 13: You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 24 and a population standard deviation 6 and a sample size of 12. Machine 2 has a sample mean of 18 and a population standard deviation of 6 with a sample size of 9. With an alpha of .05 can we claim that there is a difference between the output of the two machines. Which of the following statements are true?

A. We will not reject the null hypothesis

B. The resulting test statistic will be less than 1

C. The critical values you will use are 1.96 and -1.96

D. A and B are correct

E. A, B, and C are correct

Question 14: You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 33 and a sample standard deviation 6 and a sample size of 18. Machine 2 has a sample mean of 31 and a sample standard deviation of 6 with a sample size of 18. With an alpha of .05 can we claim that there is a difference between the output of the two machines. Which of the following statements are true?

A. We will reject the null hypothesis and prove there is a difference between the 2 populations

B. We will not reject the null hypothesis and thus we can't prove there is difference between the 2 populations

C. The critical values you will use are 1.96 and -1.96

D. B and C are correct

E. None of the above are correct

Question 15: You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 2,000.21 and a sample standard deviation 6.1 and a sample size of 2. Machine 2 has a sample mean of 1,998.76 and a sample standard deviation of 6.2 with a sample size of 2. With an alpha of .05 can we claim that there is a difference between the output of the two machines. Which of the following statements are true?

A. We will reject the null hypothesis and prove there is a difference between the 2 populations

B. We will not reject the null hypothesis and thus we can't prove there is difference between the 2 populations

C. The critical values you will use are 1.96 and -1.96

D. B and C are correct

E. None of the above are correct

Question 16: A hypothesis is always a claim about a population parameter.

A. True

B. False

Question 17: Pretend you are asked to test the claim that the true mean size of each dump truck you fill is different from 2 tons. You will have a/an...

A. lower tail test

B. upper tail test

C. two tail test

D. half tail test

E. four tail test

Question 18: Your population mean used to be 6.0. The population standard deviation is 9. The sample size is 9. The sample mean is 7.0. .05 is your level of significance. The null hypothesis is that the population mean is less than or equal to 6.0, use your sample data to test this claim. If you use this information, you will reject the null hypothesis that the population mean is less than or equal to 6.0.

A. True

B. False

Question 19: You work at a hospital that has always had about 200 employees staffed at night. You think that the number of employees staffed at night has recently increased and would like to test this claim. If you run a hypothesis test, which of the following statements would fit your problem?

A. You have a two tail test.

B. Your alternative hypothesis could be stated as the population mean is less than 100.

C. Your null hypothesis could be stated as the population mean is greater than or equal to 100.

D. B, and C are correct.

E. None of the above

Question 20: You are a manager at a firm and you believe your monthly costs have increased. The costs have always been $9,000 but you now believe they are more and would like to test this claim. If you run a hypothesis test, which of the following statements would fit your problem?

A. You have an upper tail test

B. Your alternative hypothesis could be stated as the population mean is less than 9,000

C. Your null hypothesis could be stated as the population mean is greater than or equal to 9,000.

D. A, B, and C are correct

E. Just B and C are correct

Question 21: Your population mean has always been 9 customers per hour. The sample standard deviation is 4. The sample size is 25. The sample mean is 8. .05 is your level of significance. Use your sample data to test the claim that the number of customers you are serving per hour has changed. Choose the most accurate answer to running this hypothesis test.

A. Your test statistic returns a number less than -2.0

B. You will reject the null hypothesis

C. Your n is 8

D. A and B

E. None of the above

Question 22: Your population mean has always been 100. The sample standard deviation is 2. The sample size is 16. The sample mean is 100.75. 0.2 is your level of significance. Use your sample data to test the claim that the mean is now different from the level it has always been. If you use this information, you will reject the null hypothesis that the population mean is = 100.

A. True

B. False

Reference no: EM13823621

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