MODULE 4: EXERCISE 8

Normal Distribution

Choose the correct answer among the following choices.

1. In the normal curve, the measure of variability all coincides at the center.

TRUE or FALSE

2) Suppose that the mean score of 2000 students in a certain exam is 65 points with a standard deviation of 5 points follows a normal distribution. How many of the students had a score between 55 and 75?*

A. 1365

B. 1908

C. 1958

D. 1994

3) In normally distributed data, what percent of the data lies on the interval 2 standard deviations away from the mean.

A. 68.26

B. 95.44

C. 97.94

D. 99.74

4) An important quality characteristic for softdrink bottlers is the amount of softdrink injected into each bottle. In a particular filling process, the number of ounces injected into an 8-ounce bottle is approximately normally distributed with a mean of 8.00 ounces and a standard deviation of 0.05 ounce. Bottles that contain less than 7.90 ounces do not meet the bottler's quality standard. If 20,000 bottles are filled, approximately how many will meet the quality standard?

A. 19,544

B. 11,586

C. 19,642

D. 18,426

5) In a mango farm of 250 trees, the mean harvest is 96.5 kilos of fruit per tree with a standard deviation of 8.4 kilos. Assuming that the harvests per tree are normally distributed, how many trees yielded a harvest below 100 kilos?

A. 165

B. 40

C. 171

D. 84