Exam 13: Normal Distributions

Record the death rate from heart disease per 100,000 people in a group of developed countries. The distribution is roughly described by this Normal curve: From the Normal curve, we see that the standard deviation of the heart disease rate per 100,000 people is about

The weight losses for participants in a large exercise and diet study vary according to a Normal distribution with mean 14.5 pounds and standard deviation 3 pounds. The median amount of weight lost for the participants in this study is:

The weight losses for participants in a large exercise and diet study vary according to a Normal distribution with mean 14.5 pounds and standard deviation 3 pounds. Approximately what range covers the middle 95 percent of the weight losses?

The distribution of the number of dill pickle spears in a gallon container is approximately Normal with mean 110 and standard deviation 10. If a container had to have at least 90 spears to pass quality control, approximately what percent of the containers failed? (That is, had fewer than 90 spears)?

Scores on the American College Testing (ACT) college entrance exam follow the Normal distribution with mean 18 and standard deviation 6. Wayne's standard score on the ACT was -1.1. What was Wayne's actual ACT score?

The third quartile is also called the

Scores of adults aged 60 to 64 on a common IQ test are approximately Normally distributed with mean 90 and standard deviation 15. Since IQ scores of adults aged 60 to 64 are Normally distributed with mean 90 and standard deviation 15, then about 40% of the scores are between

The weights of cockroaches follow a Normal distribution with mean 80 grams and standard deviation 2 grams. The figure below is the Normal curve for this distribution of weights. At which point on the Normal curve is the median of the distribution of cockroach weights located?

The weights of cockroaches follow a Normal distribution with mean 80 grams and standard deviation 2 grams. The figure below is the Normal curve for this distribution of weights. About what percent of the cockroaches have weights less than 78 grams?

The distribution of the number of dill pickle spears in a gallon container is approximately Normal with mean 110 and standard deviation 10. The median number of pickle spears for this sort of container:

The risk of an investment is measured by the variability of the changes in its value over a fixed period, such as a year. More variation from year to year means more risk. The government's Securities and Exchange Commission wants to require mutual funds to tell investors how risky they are. A news article (New York Times, April 2, 1995) says that some people think that "the proposed risk descriptions, especially one that goes by the daunting name standard deviation" are hard to understand. Explain to a friend what the standard deviation means, using the fact that the changes in a mutual fund's value over many years have a roughly Normal distribution.

Record the death rate from heart disease per 100,000 people in a group of developed countries. The distribution is roughly described by this Normal curve: From this Normal curve, we see that the mean heart disease death rate per 100,000 people is about

Scores on the American College Testing (ACT) college entrance exam follow the Normal distribution with mean 18 and standard deviation 6. Wayne's standard score on the ACT was -1.1. Wayne's buddy Garth took the SAT. His standard score on the SAT was 0.6. This means that Garth's actual score was

About what percent of the cockroaches have weights between 76 grams and 84 grams? The weights of cockroaches follow a Normal distribution with mean 80 grams and standard deviation 2 grams. The figure below is the Normal curve for this distribution of weights.