A) 24.57% B) -22.37% C) 22.37% D) 49.51% E) 22.39% A) 24.57% B) -22.37% C) 22.37% D) 49.51% E) 22.39%

A) 80.78% B) 82.35% C) 83.40% D) 16.60% E) 83.15% A) 80.78% B) 82.35% C) 83.40% D) 16.60% E) 83.15%

A) -1.46 to 1.46 B) -1.45 to 1.45 C) -1.39 to 1.39 D) -1.53 to 1.53 E) -1.00 to 1.00 A) -1.46 to 1.46 B) -1.45 to 1.45 C) -1.39 to 1.39 D) -1.53 to 1.53 E) -1.00 to 1.00

Exam 5: The Standard Deviation As a Ruler and the Normal Model

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A salesman's commission averages $23,700 per year.Last year his commission was $18,900 which corresponded to a z-score of -1.2.Find the standard deviation.

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Question 41

A town's average snowfall is 40 cm per year with a standard deviation of 12 cm.How many standard deviations from the mean is a snowfall of 64 cm?

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Question 42

The average size of forest fires last year was 968 acres with a standard deviation of 182 acres.How many standard deviations from the mean is a forest fire consuming 245 acres?

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Question 43

The test scores from a recent Mathematics test are as follows: 95.5,65.9,93.2,88.6,56.8,50,86.4,54.5,40.9,77.3,79.5,65.9,70.5,77.3,81.8,50,79.5,and 68.2.The mean score was 71.2 with a standard deviation of 15.5.If the Normal model is appropriate,what percent of the scores will be greater than 86.7?

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Question 44

An English instructor gave a final exam and found a mean score of 69 points and a standard deviation of 5.8 points.Assume that a Normal model can be applied.Draw and label the Normal model for the exam scores.Then find the interval for the central 68% of the scores.

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Question 45

-1.10 < z < -0.36

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Question 46

σ = 16,20% below 100; μ = ?

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Question 47

The average speed cars travel on a road is 77 km/h.A car travelling 60 km/h has a z-score of -1.7.Find the standard deviation.

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Question 48

Based on the Normal model for snowfall in a certain town N(57,8),how many cm of snow would represent the 75th percentile?

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Question 49

Assuming a Normal model applies,a town's average annual snowfall (in cm)is modeled by $\mathrm { N } ( 45,7 )$ Draw and label the Normal model.What percent of snowfall is between 52 cm and 59 cm?

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Question 50

Based on the Normal model for car speeds (in km/h)on a road N(77,9.1),what are the cutoff values for the middle 70% of the speeds?

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Question 51

σ = 150,9.18% below 900; μ = ?

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Question 52

z < 0.97

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Question 53

For a recent English exam,use the Normal model N(73,9.2)to find the score that represents the 30th percentile.

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Question 54

The average number of days absent per student per year at West Valley School is 16 days with a standard deviation of 5 days.How many standard deviations from the mean is of 6 absent days?

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Question 55

the middle 87.4%

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Question 56

The mean weight of babies born in a hospital last year was 2.84 kg.Suppose the standard deviation of the weights is 0.95 kg.Which would be more unusual,a baby weighing 1.8 kg or a baby weighing 3.83 kg? Explain.

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Question 57

After increased patrol,91% of vehicles on a road travel above 45 km/h with a standard deviation of 5.2 km/h.Assuming a Normal model is appropriate,find the mean speed.

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Question 58

For a recent English exam,use the Normal model N(73,9.2)to find the percent of scores over 85.Round to the nearest tenth of a percent.

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Question 59

μ = 300,90% below 500; σ = ?

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Question 60

Showing 41 - 60 of 111

Exam 5: The Standard Deviation As a Ruler and the Normal Model

A salesman's commission averages $23,700 per year.Last year his commission was $18,900 which corresponded to a z-score of -1.2.Find the standard deviation.

A town's average snowfall is 40 cm per year with a standard deviation of 12 cm.How many standard deviations from the mean is a snowfall of 64 cm?

The average size of forest fires last year was 968 acres with a standard deviation of 182 acres.How many standard deviations from the mean is a forest fire consuming 245 acres?

The test scores from a recent Mathematics test are as follows: 95.5,65.9,93.2,88.6,56.8,50,86.4,54.5,40.9,77.3,79.5,65.9,70.5,77.3,81.8,50,79.5,and 68.2.The mean score was 71.2 with a standard deviation of 15.5.If the Normal model is appropriate,what percent of the scores will be greater than 86.7?

An English instructor gave a final exam and found a mean score of 69 points and a standard deviation of 5.8 points.Assume that a Normal model can be applied.Draw and label the Normal model for the exam scores.Then find the interval for the central 68% of the scores.

-1.10 < z < -0.36

σ = 16,20% below 100; μ = ?

The average speed cars travel on a road is 77 km/h.A car travelling 60 km/h has a z-score of -1.7.Find the standard deviation.

Based on the Normal model for snowfall in a certain town N(57,8),how many cm of snow would represent the 75th percentile?

Assuming a Normal model applies,a town's average annual snowfall (in cm)is modeled by N(45,7)\mathrm { N } ( 45,7 )N(45,7) Draw and label the Normal model.What percent of snowfall is between 52 cm and 59 cm?

Based on the Normal model for car speeds (in km/h)on a road N(77,9.1),what are the cutoff values for the middle 70% of the speeds?

σ = 150,9.18% below 900; μ = ?

z < 0.97

For a recent English exam,use the Normal model N(73,9.2)to find the score that represents the 30th percentile.

The average number of days absent per student per year at West Valley School is 16 days with a standard deviation of 5 days.How many standard deviations from the mean is of 6 absent days?

the middle 87.4%

The mean weight of babies born in a hospital last year was 2.84 kg.Suppose the standard deviation of the weights is 0.95 kg.Which would be more unusual,a baby weighing 1.8 kg or a baby weighing 3.83 kg? Explain.

After increased patrol,91% of vehicles on a road travel above 45 km/h with a standard deviation of 5.2 km/h.Assuming a Normal model is appropriate,find the mean speed.

For a recent English exam,use the Normal model N(73,9.2)to find the percent of scores over 85.Round to the nearest tenth of a percent.

μ = 300,90% below 500; σ = ?

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Assuming a Normal model applies,a town's average annual snowfall (in cm)is modeled by $\mathrm { N } ( 45,7 )$ Draw and label the Normal model.What percent of snowfall is between 52 cm and 59 cm?