Find thezvalue to the right of the mean so that 62.93% of the area under the distribution curve lies to the left of it.

Question 1 options:

Question 2(4 points)

Find thezvalue to the right of the mean such that 85% of the total area under the standard normal distribution curve lies to the left of it?

Question 2 options:

Question 3(4 points)

What is thezvalue such that 50% of the total area under the standard normal distribution curved lies to the right of it?

Question 3 options:

Question 4(4 points)

The standard deviation of a normal distribution is 20. What is the standard error of the mean obtained by averaging 225 samples?

Question 4 options:

Question 5(4 points)

A survey of 250 lobster fishermen found that they catch an average of 32.0 pounds of lobster per day with a standard deviation of 4.0 pounds. If a random sample of 36 lobster fishermen is selected, what is the probability that their average catch is less than 31.5 pounds? Assume the distribution of the weights of lobster is normal.

Question 5 options:

Question 6(4 points)

According to a study of 90 truckers, a trucker drives, on average, 540 miles per day. If the standard deviation of the miles driven per day for the population of truckers is 40, find the 99% confidence interval of the mean number of miles driven per day by all truckers.

Question 6 options:

Question 7(4 points)

The average score for 49 teenage boys playing a certain computer game was 80,000 points per player. If the standard deviation of the population is 20,000 points, find the 95% confidence interval of the mean score for all teenage boys.

Question 7 options:

Question 8(4 points)

The average number of mosquitos caught in 81 mosquito traps in a particular environment was 900 per trap. The standard deviation of mosquitos caught in the entire population of traps is 150 mosquitos. What is the 99% confidence interval for the true mean number of mosquitos caught in all mosquito traps?

Question 8 options:

Question 9(4 points)

A sample of 400 racing cars showed that 80 of them cost over $700,000. What is the 99% confidence interval for the true proportion of racing cars that cost over $700,000?

Question 9 options:

Question 10(4 points)

A quality control expert wants to estimate the proportion of defective components that are being manufactured by his company. A sample of 300 components showed that 20 were defective. How large a sample is needed to estimate the true proportion of defective components to within 2.5 percentage points with 99% confidence?

Question 10 options:

Question 11(4 points)

Dr. Christina Cuttleman, a nutritionist, claims that the average number of calories in a serving of popcorn is 75 with a standard deviation of 7. A sample of 50 servings of popcorn was found to have an average of 78 calories. Check Dr. Cuttleman's claim at =0.05.

Question 11 options:

Question 12(4 points)

The average magnesium concentration in ground water around Metro City isparts per million (ppm) with a standard deviation of. The table below shows the ground-water magnesium concentrations (ppm) from random sites in a suburb located 15 miles away. At, can it be concluded that the average magnesium concentration in the suburb differs from 86.2 ppm?102

107

45

90

74

10

109

94

61

108

88

71

46

110

112

64

94

34

42

108

121

125

72

46

108

51

5

92

104

52

77

12

53

90

116

a. State the hypotheses and identify the claim.

b. Find the critical values.

c. Compute the test statistic.

d. Make a decision.

e. Summarize the results.

Question 12 options:

Question 13(4 points)

A manufacturer claims that its televisions have an average lifetime of at least five years (60 months) with a population standard deviation of seven months. Eighty-one televisions were selected at random, and the average lifetime was found to be 59 months. With= 0.025, is the manufacturer's claim supported?

Question 13 options:

Question 14(4 points)

Reginald Brown, an inspector from the Department of Weights and Measures, weighed 15 eighteen-ounce cereal boxes of corn flakes. He found their mean weight to be 17.8 ounces with a standard deviation of 0.4 ounces. At= 0.01, are the cereal boxes lighter than they should be?

Question 14 options:

Question 15(4 points)

Science fiction novels average 250 pages in length. The average length of 10 randomly chosen novels written by I. M. Wordy was 295 pages in length with a standard deviation of 60. At= .05, are Wordy's novels significantly longer than the average science fiction novel?

Question 15 options:

Question 16(4 points)

It has been claimed that at UCLA at least 40% of the students live on campus. In a random sample of 250 students, 90 were found to live on campus. Does the evidence support the claim at= .01?

Question 16 options:

Question 17(4 points)

A random sample of 450 shoppers at Quincy Mall found that 125 favored longer shopping hours. Is this sufficient evidence at the 0.05 level of significance to conclude that less than 30% of the shoppers at Quincy Mall favor longer hours?

Question 17 options:

Question 18(4 points)

A conservationist suspects that the water level in Horseshoe Lake has been affected more by the current drought than the water level in Swan Lake, so he measures how far the water level is below normal each day in June. The data are normally distributed. Test his hypothesis at= 0.01.

Horseshoe Lake

Swan Lake

Question 18 options:

Question 19(4 points)

Joan has just moved into a new apartment and wants to purchase a new couch. To determine if there is a difference between the average prices of couches at two different stores, she collects the following data. Test the hypothesis that there is no difference in the average price. Use =0.05.

Store 1Store 2

Question 19 options:

Question 20(4 points)

The average credit card debt for a recent year was $9540. Five years earlier the average credit card debt was $8880. Assume sample sizes of 34 were used and the population standard deviations of both samples were $1069. Is there evidence to conclude that the average credit card debt has increased? Use.

a. State the hypotheses.

b. Find the critical value.

c. Compute the test statistic.

d. Make the decision.

e. Summarize the results.

Question 20 options:

Question 21(4 points)

The number of calories in a 12-ounce serving of randomly-selected regular and lite beers is listed. Is there sufficient evidence to conclude that the mean number of calories for lite beers is significantly less than that for the regular beers? Use. Assume the variables are approximately normally distributed.Regular:131

134

184

111

101

165

155

136

120

113

154

131

143

Lite:82

191

126

108

126

108

113

143

124

62

a.State the hypotheses.

b. Find the critical value(s).

c. Compute the test value.

d. Make the decision.

e. Summarize the results.

Question 21 options:

Question 22(4 points)

Find the equation of the regression line.

Question 22 options:

Question 23(4 points)

A psychologist wants to determine if there is a linear relationship between the number of hours a person goes without sleep and the number of mistakes he/she makes on a simple test. The following data is recorded.

a. Draw a scatter plot.

b. Determine the regression line equation and plot the regression line

on the scatter plot.

Hours without Sleep,x

Number of Mistakes,y

32

6

38

8

48

13

24

5

46

7

35

6

30

5

34

8

42

12

Question 23 options:

Question 24(4 points)

A realtor wanted to determine if there was a relationship between the size (in 100 square feet) of a new custom-built home and the price (in thousands of dollars) of the home.

a. Draw a scatter plot.

b. Determine the regression line equation and plot the regression line

on the scatter plot.

Size,x

Price,y

26

235

27

273

41

387

29

253

33

295

34

335

36

395

45

475

22

203

Question 24 options:

Question 25(4 points)