Normal Probability Distributions

The mean temperature in Glens Falls for the month of February is 23 degrees with a standard deviation of 4.2 degrees.  Approximately what percent of days in February will have days below 23 degrees?

• 5%

• 34%

• 50%

• 68%

The average height of NBA basketball players is 79 inches with a standard deviation of 1.75 inches. Approximately what percent of the players are taller than 82 inches?

• about 4% to 5%

• about 2% to 3%

• about 6% to 7%

• about 6.5%c to 7.5%

The distribution of SAT scores of all college-bound seniors taking the SAT in 2014 was approximately normal with mean of 1497

and standard deviation of 322. Calculate the z-score of a student earning a score of 1980.

.

• 2

• 1.5

• 1.75

• 2.25

For the population of farm workers in New Zealand, suppose that weekly income has a distribution with a mean of µ = $500 and a standard deviation of σ = $160. A survey of 100 farm workers is taken, including information on their weekly income. What is the probability that a randomly selected worker has an income of at most $530?

• 0.0304

• 0.9696

• 0.4591

• 0.318

• ~0

The mean weight of potato chip bags is 10.5 ounces with a standard deviation of 3 ounces. A random sample of 40 bags of potato chips is selected. What is the probability that the mean of the sample is less than 10 ounces?

• -1.05

• .146

• .020

• .853

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 probability that the mean number of gallons of fuel needed to take off for a randomly selected sample of 40 jumbo jets will be less than 3950 gallons?

• .0057

• .025

• .345

• .781

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.  What is the probability that a randomly selected group of 35 high school students get more than 6 hours of sleep each night?

• .430

• .148

• .281

• .087

The average speed of 1500 vehicles traveled on a stretch of highway that 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 mean distance an OHS student travels to school is 5.6 miles with a standard deviation of 1.7 miles. Mrs. McLemore finds the mean of her 4th period class - a randomly selected sample of 39 students. What is the probability that the mean of her class is more than 6 miles?

• 0.002

• 0.070

• 0.898

• 1.27

There were 5,317 previously owned homes sold in a western city in the year 2000. The distribution of the sales prices of these homes was strongly right-skewed, with a mean of $206,274 and a standard deviation of $37,881. If all possible simple random samples of size 100 are drawn from this population and the mean is computed for each of these samples, which of the following describes the sampling distribution of the sample mean?

• Approximately normal with mean $206,274 and standard deviation $3,788

• Approximately normal with mean $206,274 and standard deviation $37,881

• Approximately normal with mean $206,274 and standard deviation $520

• Strongly right-skewed with mean $206,274 and standard deviation $3,788

• Strongly right-skewed with mean $206,274 and standard deviation $37,881