Sample Distribution

The mean and standard deviation of a population are 200 and 20, respectively. Sample size is 25. 
What is the mean of the sampling distribution?

• 200

• 16

• 25

• 4

The mean and standard deviation of a population are 200 and 20, respectively. Sample size is 25. 
What is the standard deviation of the sampling distribution?

• 200

• 16

• 25

• 4

Thirty randomly selected students took the calculus final. If the sample mean was 92 and the population standard deviation was 9.4, construct a 99 percent confidence interval for the mean score of all students from which the sample was gathered.

• 89.08 < μ < 94.92

• 87.57 < μ < 96.43

• 87.29 < μ < 96.71

• 87.77 < μ < 96.23

In a crash test of 15 troopers, collision repair costs are found to have a distribution that is approximately normal, with a mean of $1800 and a population standard deviation of $950. Construct a 99% confidence interval for the repair cost for the population.

• (1167, 2433)

• (1273, 2326)

• (1799, 1801)

• (1776, 1823)

The lifetime of a certain type of batter is known to be normally distributed with a population standard deviation of 20 hours. A sample of 50 batteries had a mean lifetime of 120.1 hours. It is desired to construct a 99% confidence interval for the mean lifetime of this type of battery.

What is the Confidence Interval to one decimal place?

• (114.5, 125.6)

• (112.8, 127.4)

• (112.82, 127.38)

• (114.56, 125.64)

The height of women is normally distributed with an average height of 64 inches and a standard deviation of 2.5 inches. What interval contains 99.7% of all data?

• 61.5 to 66.5

• 56.5 to 71.5

• 59 to 69

• 2.5 to 99.7

Find the class width:

• 3

• 4

• 5

• 19

Estimate the frequency of the class with the greatest frequency.

• 28

• 21

• 58

• 53

What class has the greatest frequency? Those with the ages...

• 28

• 18

• 58

• 38

Describe the distribution of the histogram

• symmetric

• bimodal

• skew left

• skew right