Estimating Population Mean Sigma Known

• 5

• 0

The average speed of 1500 vehicles traveling on a stretch of highway one particular day is 67 miles per hour with a standard deviation of 3.5 miles per hour. If 100 vehicles are randomly selected as samples, what would be the mean of the resulting sampling distribution of sample means?

• 63.5

• 67

• 70.5

• 74

The amount of fuel used by jumbo jets to take off is normally distributed with a mean of 4000 gallons and a standard deviation of 125 gallons. What is the shape, mean and standard deviation of the distribution of sample means from samples of size n = 81.

• Normal,  $\mu_x$  = 4000,  $\sigma_x$  = 1.543

• Normal,  $\mu_x$  = 4000,  $\sigma_x$  = 13.89

• Normal,  $\mu_x$  = 444,  $\sigma_x$  = 13.89

Suppose the teenagers that attend public high schools get an average of 5.7 hours of sleep each night with a standard deviation of 1.7 hours. The distribution of sleep time is skewed to the left. What is the shape, mean, and standard deviation of the distribution of sample means from samples of size n = 400?

• Skewed Left, $\mu_x$ = 5.7 hours $\sigma_x$ = 0.085 hours

• Approximately Normal, $\mu_x$ = 5.7 hours $\sigma_x$ = 1.7 hours

• Skewed Left, $\mu_x$ = 5.7 hours $\sigma_x$ = 1.7 hours

Researchers found that boys playing high school football absorb an average of 355 hits to the head with a standard deviation of 80 hits during a season. If samples of 48 high school football players are randomly selected, what is the shape, mean and standard deviation of the distribution of sample means?

• Normal, $\mu_x$ = 355 , $\sigma_x$ = 11.547

• Approximately Normal, $\mu_x$ = 355 , $\sigma_x$ = 11.547

• Normal, $\mu_x$ = 355 , $\sigma_x$ = 80

These symbols represent the mean and standard deviation for which of the following distributions?

• The Population Distribution

• The Distribution of the Sample

• The Distribution of the Sample Means (Sampling Distribution)

Consider a population which is normally distributed. If σ²=9 and n=16, what is the variance of the sampling distribution of sample means? (Do not round off)

Consider a population which is normally distributed. If\sigma=2 and n=9 , what is the standard deviation of the sampling distribution of sample means?

• 0.67

• 0.22

• 0.44

• 1.33

Cellular phone bills for residents of a city have a mean of P1,000 and a standard deviation of P170. Random samples of 100 cellular phone bills are drawn from this population and the mean of each sample is determined. Find the mean of the sampling distribution of sample means.

• 1000

• 170

• 100

• 17