Introduction to Normal Distributions Answers

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 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 annual salaries of all employees at a financial company are normally distributed with a mean of $34,000 and a standard deviation of $4,000. What is the z-score of a company employee who makes an annual salary of $54,000?

The weights of boxes of candies produced in a factory are normally distributed with a mean weight of 16 oz and a standard deviation of 1 oz. What is the weight of a box of candies with a z-score of 2?

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

The lengths of a certain species of fish are approximately normally distributed with a given mean and standard deviation . According to the Empirical Rule, what percentage of the fish will have lengths within 1 standard deviation of the mean?

The graph below shows two normal distributions.What is the difference of the means of the distributions?

What is the mean of the normal distribution shown below?

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?