2.2 Normal Distributions

The weights of adult male beagles are normally distributed, with a mean of 25 pounds and a standard deviation of 3 pounds. A beagle is randomly selected. Find the probability that the beagle’s weight is between 23 and 26 pounds.

• 0.3694

• 0.3779

• 0.0912

• 0.6221

The weights of adult male beagles are normally distributed, with a mean of 25 pounds and a standard deviation of 3 pounds. A beagle is randomly selected. Find the probability that the beagle’s weight is more than 29 pounds.

• 0.9082

• 0.3781

• 0.0917

• 0.2431

A z-score tells you...

• the standard deviation of a sampling distribution.
• the original raw score on which it is based.
• if the distribution it comes from is normal.
• how many standard deviations away from the mean a score lies.

Find the area under the standard normal curve between z = -2.55 and z = 1.08. 

• 0.8545
• 0.7560
• 0.3110
• 0.2140

The mean life of a tire is 30,000 km. The standard deviation is 2000 km.

Then, 68% of all tires will have a life between ___________ km and __________ km.

•  28,000 km and 32,000 km.
• 24,000 km and 34,000 km.
• 26,000 km and 34,000 km.
• 27,000 km and 31,000 km.

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days.

About what percent of the products last between 12 and 15 days? (Use the 68-95-99.7 Rule)

• 68%

• 34%

• 16%

• 2.5%

The percentile represents the....

• percent of data values that are below.
• percent of data values that are above.
• number of data values that are below.
• number of data values that are below.

Annual U.S. per capita orange use: μ =11.4 lb, σ = 3lb. What annual per capita use of oranges represents the 10th percentile?

• 7.56 lbs
• 13.42 lbs
• 8.29 lbs 
• 9.38 lbs

Tags

CCSS.HSS.ID.A.4

CCSS.HSS.MD.A.1

CCSS.HSS.MD.A.3

In a survey of men in the United States (ages 20-29), the mean height was 69.6 inches with a standard deviation of 3.0 inches. Find the minimum height in the top 22%.

• 69.37 in

• 67.29 in

• 71.91 in

• 77.21 in