107_7.2_notes_quiz

What is the z-score of a data value that is 3 standard deviations above the mean?

• 0

• 1

• 2

• 3

To find the area to the left of a given z-score on a general normal curve, you should first ______.

• convert to a t-score

• standardize to z-scores

• use the mean

• find the median

What is the probability that a pregnancy lasts longer than 280 days if the length of pregnancy is approximately normally distributed with a mean of 272 days and a standard deviation of 9 days?

• 0.1867

• 0.8133

• 0.9106

• 0.0894

Fill in the blank: If a normal population has a mean of 56 and a standard deviation of 12, the probability that a randomly sampled value is between 60 and 70 is ____.

• 0.2497

• 0.3790

• 0.6239

• 0.0968

What is the formula to find the value of x that corresponds to a given z-score in a normal distribution?

• x = μ + σz

• x = zσ + μ

• x = μz + σ

• x = σ + μz

In a group of men, heights are normally distributed with a mean of 69 inches and a standard deviation of 3 inches. If the z-score is 0.6, what is the height?

• 70.8 inches

• 71.2 inches

• 68.4 inches

• 69.6 inches

• 4.5

• 5.18

• 6.2

• 7.1

• 60.5

• 66.26

• 70.1

• 75.3

A normal population has mean μ = 3 and standard deviation σ = 2.6. What is the 80th percentile of the population?

• 4.5

• 5.18

• 6.2

• 7.0

A normal population has mean μ = 27 and standard deviation σ = 12. Find the values that separate the middle 60% of the population from the rest. Fill in the blank: The values are ______ and 37.08.

• A) 20.76

• B) 22.5

• C) 25.0

• D) 30.0