The mean annual incomes of certified welders are normally distributed

1.The mean annual incomes of certified welders are normally distributed with the mean of $50,000 and a population standard deviation of $2,000. The ship building association wishes to find out whether their welders earn more or less than $50,000 annually. A sample of 100 welders is taken and the mean annual income of the sample is $50,350. If the level of significance is 0.10, what conclusion should be drawn? 选项： A:

Do not reject the null hypothesis as the test statistic is less than the critical value of t.

B:

Reject the null hypothesis as the test statistic is greater than the critical value of z.

C:

Do not reject the null hypothesis as the test statistic is less than the critical value of z.

D:

Reject the null hypothesis as the test statistic is greater than the critical value of t.

2.A p-value is equal to the:选项： A:population proportion.; B:significance level.; C:fraction of the population that has a particular characteristic.; D:probability of finding a value of the test statistic that is equal or more extreme (greater than or less than) than the value of the test statistic assuming the null hypothesis is true.

3.A ________ is a numerical quantity computed from the data of a sample and is used in reaching a decision on whether or not to reject the null hypothesis. A: significance level B: critical value C: test statistic D: parameter

4.A ________ is a numerical quantity computed from the data of a sample and is used in reaching a decision on whether or not to reject the null hypothesis.选项： A:significance level; B:critical value; C:test statistic; D:parameter

5.A ________ is a numerical quantity computed from the data of a sample and is used in reaching a decision on whether or not to reject the null hypothesis.(2.0) 选项： A、significance level B、critical value C、test statistic D、parameter

6.36.A ________ is a numerical quantity computed from the data of a sample and is used in reaching a decision on whether or not to reject the null hypothesis. 选项： A、significance level B、critical value C、test statistic D、parameter

7.The manufacturers of a deodorant claim that the mean drying time of their product is, at most, 15 minutes. A sample consisting of 16 cans of the product was used to test the manufacturer’s claim. The experiment yielded a mean drying time of 18 minutes with a standard deviation of 6 minutes. Test the claim at the 0.05 significance level.选项： A:Computed test statistic = 2 and is greater than 1.645, so reject H0: µ ≤ 15. B:Computed test statistic = 2 and is greater than 1.96, so reject H0: µ ≤ 15. C:Computed test statistic = 2 and is greater than 1.753, so reject H0: µ = 15. D:Computed test statistic = 2 and is greater than 2.131, so reject H0: µ ≤ 15.

8.The manufacturers of a deodorant claim that the mean drying time of their product is, at most, 15 minutes. A sample consisting of 16 cans of the product was used to test the manufacturer’s claim. The experiment yielded a mean drying time of 18 minutes with a standard deviation of 6 minutes. Test the claim at the 0.05 significance level.选项： A:Computed test statistic = 2 and is greater than 1.96, so reject H0: µ ≤ 15. B:Computed test statistic = 2 and is greater than 1.753, so reject H0: µ = 15. C:Computed test statistic = 2 and is greater than 1.645, so reject H0: µ ≤ 15. D:Computed test statistic = 2 and is greater than 2.131, so reject H0: µ ≤ 15.

9.Using the confidence interval when conducting a two-tail test for the population mean we do not reject the null hypothesis if the hypothesised value for µ:

10.A test statistic is a numerical quantity computed from the data of a sample and is used in reaching a decision on whether or not to reject the null hypothesis.A．正确B．错误

11.A test statistic is a numerical quantity computed from the data of a sample and is used in reaching a decision on whether or not to reject the null hypothesis.选项： A:对 B:错

12.A random sample of 50 FRM exam candidates was found to have an average IQ of 125. The standard deviation among candidates is known (approximately 20). Assuming that IQs follow a normal distribution, carry out a statistical test (5% significance level) to determine whether the average IQ of FRM candidates is greater than 120. Compute the test statistic and give a conclusion. 选项： A:Test statistic: 1.768; Reject H0 B:Test statistic: 2.828; Reject H0 C:Test statistic: 1.768; Fail to reject H0 D:Test statistic: 1.0606; Fail to reject H0

13.What type of hypothesis states that the sample statistic is not the same as the population statistic but is either greater than or less than, but not both? 选项： A:Null B:One-tailed C:Two-tailed D:Three-tailed E:None of the above is correct.

14.A random sample of 50 CFA exam candidates was found to have an average IQ of 125. The standard deviation among candidates is known (approximately 20). Assuming that IQs follow a normal distribution, carry out a statistical test (5% significance level) to determine whether the average IQ of CFA candidates is greater than 120. Compute the test statistic and give a conclusion. 选项： A: Test statistic: 1.768; Reject H0 B: Test statistic: 1.768; Fail to reject H0 C: Test statistic: 1.0606; Fail to reject H0

15.A researcher is interested in testing to determine if the mean of population one is greater than the mean of population two. The null hypothesis is that there is no difference in the population means (i.e. the difference is zero). The alternative hypothesis is that there is a difference (i.e. the difference is not equal to zero). He randomly selects a sample of 9 items from population one resulting in a mean of 14.3 and a standard deviation of 3.4. He randomly selects a sample of 14 items from population two resulting in a mean of 11.8 and a standard deviation 2.9. He is using an alpha value of .10 to conduct this test. Assuming that the populations are normally distributed, the critical t-value from the table is _______.选项： A:1.323 B:1.721 C:1.717 D:1.321

16.Suppose, in testing a hypothesis about a mean, the Z test statistic is computed to be 2.04. The null hypothesis should be rejected if the chosen level of significance is 0.01 and a two-tail test is used.

17.Which of the following would be an appropriate null hypothesis? 选项： A、 The mean of a population is equal to 55. B、The mean of a sample is equal to 55. C、 The mean of a population is greater than 55. D、 The mean of a population is less than 55.

18.Suppose, in testing a hypothesis about a mean, the Z test statistic is computed to be 2.04. The null hypothesis should be rejected if the chosen level of significance is 0.01 and a two-tail test is used. 选项： A、正确 B、错误

19.If we reject the null hypothesis, what can we conclude subject to the probability, α? 选项： A:

Reject the null with a probability, α, of making a Type I1 error.

B:

The alternative hypothesis is false.

C:

The null hypothesis is true.

D:

Both the null hypothesis and the alternative hypothesis are true.

20.Suppose, in testing a hypothesis about a mean, the Z test statistic is computed to be 2.04. The null hypothesis should be rejected if the chosen level of significance is 0.01 and a two-tail test is used.选项： A:正确; B:错误

21.A researcher is performing a two-tailed related samples (matched pairs) t-test. A total of 12 people are in the sample, and before and after measures are taken. The observed t-value for this is –1.84. The level of significance is 0.05. The correct decision is to _______.选项： A:do not reject the null hypothesis B:reject the null hypothesis C:take a larger sample D:use the z-table instead of the t-table

22.A researcher is interested in testing to determine if the mean of population one is greater than the mean of population two. The null hypothesis is that there is no difference in the population means (i.e. the difference is zero). The alternative hypothesis is that there is a difference (i.e. the difference is not equal to zero). He randomly selects a sample of 9 items from population one resulting in a mean of 14.3 and a standard deviation of 3.4. He randomly selects a sample of 14 items from population two resulting in a mean of 11.8 and a standard deviation 2.9. He is using an alpha value of .10 to conduct this test. Assuming that the populations are normally distributed, the degrees of freedom for this problem are _______.选项： A:23 B:22 C:15 D:2

23.A researcher is interested in testing to determine if the mean of population one is greater than the mean of population two. The null hypothesis is that there is no difference in the population means (i.e. the difference is zero). The alternative hypothesis is that there is a difference (i.e. the difference is not equal to zero). He randomly selects a sample of 9 items from population one resulting in a mean of 14.3 and a standard deviation of 3.4. He randomly selects a sample of 14 items from population two resulting in a mean of 11.8 and a standard deviation 2.9. He is using an alpha value of .10 to conduct this test. Assuming that the populations are normally distributed, the degrees of freedom for this problem are _______.选项： A:23 B:22 C:21 D:2