Compute the mean for a sample with n = 6 and image= 72 (Points : 4) 12
432
6
0.083

You are performing a study about the weight of preschoolers. A previous study found the weights to be normally distributed with a mean of 30 and a standard deviation of 4. You randomly sample 30 preschool children and find their weights to be as follows.

25

25

26

26.5

27

27

27.5

28

28

28.5

29

29

30

30

30.5

31

31

32

32.5

32.5

33

33

34

34.5

35

35

37

37

38

38

a) Find the mean and standard deviation of your sample.
b) Is there a high probability that the mean and standard deviation of your sample are consistent with those found in previous studies? Explain your reasoning. (Points

A population has a standard deviation of 4.5. Calculate the standard error for a sample of size 20 taken from this population. (Points : 4) 1.006

2.33
1.96
1.88

A normally-distributed population has a mean µ = 25 and a standard deviation s = 6. For a set of samples of size 10 taken from this population, about 68.3% of the means will be in what interval? (Points : 4) 22.10, 25.90
23.10,26.90

20.00, 22,00
23.23, 27.27

A normally-distributed population has a mean µ = 40 and a standard deviation s = 12. For a set of samples of size 12 taken from this population, what is the z-value for the proportion of the sample means that will be greater than 45? (Points : 4) 2.433
1.899
1.600
1.443

Question 16. 16. A sample of size 24 is taken from a normally-distributed population. The sample shows a sample mean X = 25 and a sample standard deviation s = 6. What is the estimated standard error of the mean? (Points : 4)
0.98
1.225

2.31
1.77

Question 17. 17. Construct a 95% confidence interval for a population mean. The sample mean is X = 19 and the standard error of the mean is sX = 3.
(Points : 4)
draw no conclusion
12.12, 24.24
13.12, 24.88

reject image.
13.89, 26.88

Question 18. 18. The total number of cars in a parking lot is 1342. Out of all those cars, 417 are white or silver. What is the probability of selecting a car that is neither white nor silver, if picked randomly out of the lot? (Points : 4)
0.389 and 38.9%.

0.589 and 58.9%.

0.689 and 68.9%.

0.489 and 48.9%.

Question 19. 19. Determine the z-score for a measurement of X = 105, for a population with mean µ = 93 and standard deviation s = 5. (Points : 4)
2.112
2.4
1.87
2.8

Question 20. 20. Find the mean for the given sample data using Microsoft Excel. Unless indicated otherwise, round your answer to one more decimal place than is present in the original data values.
Last year, nine employees of an electronics company retired. Their ages at retirement are listed below. Find the mean retirement age.

51

61

62

54

68

58

60

57

54
(Points : 4)

Given the linear correlation coefficient r and the sample size n, using Microsoft Excel, determine the critical values of r and use your finding to state whether or not the given r represents a significant linear correlation. Use a significance level of 0.05.
r = 0.523, n = 25 (Points : 4)

Find the value of the linear correlation coefficient r using Microsoft Excel.

x

62

53

64

52

52

54

58

y

158

176

151

164

164

174

162

(Points : 4)

Use the given data in Microsoft Excel to find the best predicted value of the response variable.
The regression equation relating attitude rating (x) and job performance rating (y) for the employees of a company is y=11.7 + 1.02x Ten pairs of data were used to obtain the equation. The same data yield r = 0.863 and y = 80.1 What is the best predicted job performance rating for a person whose attitude rating is 77? (Points : 4)

. Use the given data to find the equation of the regression line. Round the final values to three significant digits, if necessary.

x

0

3

4

5

12

y

8

2

6

9

12

(Points : 4)

Use the given data to find the equation of the regression line. Round the final values to three significant digits, if necessary.
Managers rate employees according to job performance and attitude. The results for several randomly selected employees are given below.

Performance

59

63

65

69

58

77

76

69

70

64

Attitude

72

67

78

82

75

87

92

83

87

78

(Points : 4)

Compute the mean for a sample with n = 6 and image= 72 (Points : 4) 12
432
6
0.083

You are performing a study about the weight of preschoolers. A previous study found the weights to be normally distributed with a mean of 30 and a standard deviation of 4. You randomly sample 30 preschool children and find their weights to be as follows.

25

25

26

26.5

27

27

27.5

28

28

28.5

29

29

30

30

30.5

31

31

32

32.5

32.5

33

33

34

34.5

35

35

37

37

38

38

a) Find the mean and standard deviation of your sample.
b) Is there a high probability that the mean and standard deviation of your sample are consistent with those found in previous studies? Explain your reasoning. (Points

A population has a standard deviation of 4.5. Calculate the standard error for a sample of size 20 taken from this population. (Points : 4) 1.006

2.33
1.96
1.88

A normally-distributed population has a mean µ = 25 and a standard deviation s = 6. For a set of samples of size 10 taken from this population, about 68.3% of the means will be in what interval? (Points : 4) 22.10, 25.90
23.10,26.90

20.00, 22,00
23.23, 27.27

A normally-distributed population has a mean µ = 40 and a standard deviation s = 12. For a set of samples of size 12 taken from this population, what is the z-value for the proportion of the sample means that will be greater than 45? (Points : 4) 2.433
1.899
1.600
1.443

Question 16. 16. A sample of size 24 is taken from a normally-distributed population. The sample shows a sample mean X = 25 and a sample standard deviation s = 6. What is the estimated standard error of the mean? (Points : 4)
0.98
1.225

2.31
1.77

Question 17. 17. Construct a 95% confidence interval for a population mean. The sample mean is X = 19 and the standard error of the mean is sX = 3.
(Points : 4)
draw no conclusion
12.12, 24.24
13.12, 24.88

reject image.
13.89, 26.88

Question 18. 18. The total number of cars in a parking lot is 1342. Out of all those cars, 417 are white or silver. What is the probability of selecting a car that is neither white nor silver, if picked randomly out of the lot? (Points : 4)
0.389 and 38.9%.

0.589 and 58.9%.

0.689 and 68.9%.

0.489 and 48.9%.

Question 19. 19. Determine the z-score for a measurement of X = 105, for a population with mean µ = 93 and standard deviation s = 5. (Points : 4)
2.112
2.4
1.87
2.8

Question 20. 20. Find the mean for the given sample data using Microsoft Excel. Unless indicated otherwise, round your answer to one more decimal place than is present in the original data values.
Last year, nine employees of an electronics company retired. Their ages at retirement are listed below. Find the mean retirement age.

51

61

62

54

68

58

60

57

54
(Points : 4)

Given the linear correlation coefficient r and the sample size n, using Microsoft Excel, determine the critical values of r and use your finding to state whether or not the given r represents a significant linear correlation. Use a significance level of 0.05.
r = 0.523, n = 25 (Points : 4)

Find the value of the linear correlation coefficient r using Microsoft Excel.

x

62

53

64

52

52

54

58

y

158

176

151

164

164

174

162

(Points : 4)

Use the given data in Microsoft Excel to find the best predicted value of the response variable.
The regression equation relating attitude rating (x) and job performance rating (y) for the employees of a company is y=11.7 + 1.02x Ten pairs of data were used to obtain the equation. The same data yield r = 0.863 and y = 80.1 What is the best predicted job performance rating for a person whose attitude rating is 77? (Points : 4)

. Use the given data to find the equation of the regression line. Round the final values to three significant digits, if necessary.

x

0

3

4

5

12

y

8

2

6

9

12

(Points : 4)

Use the given data to find the equation of the regression line. Round the final values to three significant digits, if necessary.
Managers rate employees according to job performance and attitude. The results for several randomly selected employees are given below.

Performance

59

63

65

69

58

77

76

69

70

64

Attitude

72

67

78

82

75

87

92

83

87

78

(Points : 4)