Introduction to Normal Distributions Answers

The graph below shows the average daily temperatures on January 1 from 1900 to 1934 for city A.The mean of the temperatures in the chart is 24° with a standard deviation of 4°. Which temperature is more than one standard deviation above the mean?

The average miles per gallon of a particular automobile model are approximately normally distributed with a given mean = 43.8 miles per gallon and standard deviation = 5.1 miles per gallon. What percentage of the automobiles have an average miles per gallon between 38.7 miles per gallon and 48.9 miles per gallon?

The heights of a certain type of tree are approximately normally distributed with a mean height = 5 ft and a standard deviation = 0.4 ft. Which statement must be true?

The amount of daily time that teenagers spend on a brand A cell phone is normally distributed with a given mean = 2.5 hr and standard deviation = 0.6 hr. What percentage of the teenagers spend more than 3.1 hr?

The graph below shows the average daily temperatures on January 1 from 1900 to 1934 for city A.The mean of the temperatures in the chart is 24° with standard deviation of 4°. How many years had temperatures within one standard deviation of the mean?

The weights of 2-pound bags of Best Dog Food are approximately normally distributed with a given mean and standard deviation . According to the Empirical Rule, what percentage of the bags will have weights within 3 standard deviations of the mean?

The set of life spans of an appliance is normally distributed with a mean = 48 months and a standard deviation = 8 months. What is the z-score of an appliance that stopped working at 64 months?

The graph below shows the average daily temperatures on January 1 from 1900 to 1934 for city A.The mean of the temperatures in the chart is 24° with a standard deviation of 4°. Which temperature is within one standard deviation of the mean?

The class scores of a history test have a normal distribution with a mean = 79 and a standard deviation = 7. If Opal’s test score was 72, which expression would she write to find the z-score of her test score?

The graph below shows three different normal distributions.Which statement must be true?