1. When conducting a significance test for paired data you need to determine the

Question

1. When conducting a significance test for paired data you need to determine the p-value for which of the following?

Select one:

a. n - 1 degrees of freedom

b. the standard error

c. significance level

d. s (sample standard deviation)

e. x-bar

2. Recently, a price war has developed among retailers selling Brand X denim jeans. A major chain buyer wishes to estimate the mean price of these jeans during this period to compare it to the normal selling price of $20.00. A random sample of 7 major retailers produces a mean retail price of $13.50 with a standard deviation of $3.50. A 80% confidence interval for the true mean retail price of Brand X jeans during the price war is:

Select one:

a. (10.93, 16.07)

b. (11.60, 15.40)

c. (8.46, 18.54)

d. (11.81, 15.19)

e. (10.00, 17.00)

3. In an investigation on toxins produced by molds that infect corn crops, a biochemist prepares extracts of the mold culture and then measures the amount of the toxic substance per gram of solution. From six preparations of the mold culture the following observations on toxic substances (mg) are obtained: 1.2, .8, .6, 1.1, 1.2, .8.

A 95% confidence interval for the mean amount of toxic substances is:

Select one:

a. .95 ± 2.57 (.25)

b. .95 ± 1.96 (.10)

c. .95 ± 2.57 (.10)

d. .95 ± 1.96 (.25)

e. .95 ± 2.02 (.10)

4.Which of the following statements is not true about samples that can be treated as matched pairs data?

I. Data collected on these samples is analyzed by calculating the differences between paired observations and using that data in one sample tests.

II. Each value in the first group of numbers has a relationship to a value in the second group.

III. It's best to analyze related samples by conducting hypothesis tests on the mean from the first and the second groups, in that order.

Select one:

a. II only

b. II and III only

c. I, II, and III

d. I and III only

e. III only

5. Which of the following statements are true about matched pairs analysis?
I. In a matched pair analysis you use a single-sample procedure. The sample is made up of the difference between pairs of observations.

II. In a matched pairs analysis the two original samples are said to be dependent on each other.

III. In a matched pairs analysis each of the two original samples is analyzed separately before comparing their means.

IV. In a matched pairs analysis you start with two sets of observations on a single variable.

Select one:

a. II and III only

b. III and IV only

c. I, II, and III only

d. I and II only

e. I, II, and IV only

6. The diameter of ball bearings are known to be normally distributed with unknown mean and variance. A random sample of size 25 gave a mean 2.5 cm. The 95% confidence interval had length 4 cm. Then

Select one:

a. The sample variance is 4.86.

b. The sample variance is 26.03.

c. The population variance is 4.84.

d. The population variance is 23.47.

e. The sample variance is 23.47.

7. A random sample of 4 Herefords, each with a frame size of three (on a one-to-seven scale), gave a sample mean weight of 452 kg and a sample std. deviation of 12 kg. A 95% confidence interval for the average weight of all Herefords of this frame size is:

Select one:

a. (435.3, 468.7)

b. (432.9, 471.1)

c. (440.2, 463.8)

d. (428.5, 475.5)

e. (436.6, 467.4)

8. A random sample of 9 experimental plots of farm gave a sample mean yield of 150 bushels of grain and a sample standard deviation of 20 bushels. A 98% confidence interval for the average yield of grain for a plot of land is:

Select one:

a. (136.9, 163.1)

b. (144.8, 155.2)

c. (132.8, 167.2)

d. (130.7, 169.3)

e. (145.7, 154.4)

9. In order to compare two kinds of feed, thirteen pigs are split into two groups, and each group received one feed. The following are the gains in weight (kilograms) after a fixed period of time:

   Feed A: 8.0      7.4   5.8     6.2    8.8     9.5   Feed B: 12.0    18.2   8.0     9.6    8.2     9.9     10.3

We wish to test the hypothesis that Feed B gives rise to larger weight gains. The output from JMP is as follows:

                                                                           t-test

                                   Difference                      t-Test           DF            Prob>|t|

              Estimate                  -3.26905                   ** hidden**       11              0.0566

              Std Error                   1.53464

              Lower 95%               -6.64677

              Upper 95%                 0.10868

              Assuming equal variances

The appropriate null and alternate hypotheses are

Select one:

b. Ho: µA = µB Ha: µA > µB

d. Ho: µA = µB Ha: µA < µB

10. Which of the following is a characteristic of the t distribution?

Select one:

a. It contains a finite number of terms.

b. It shape depends on the number of degrees of freedom.

c. It's identical to the normal curve.

d. Its median is positive.

Explanation / Answer

1. Answer (a)

2. Answer (b)

3. Answer (b)

4. Answer (e)

5. Answer (e)

6. Answer (b)

7, Answer (b)

8. Answer (d)

9. Answr (d)

10. Answer (b)

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