Applications with Standard Normal Distribution Answers

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 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 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?

What is the mean of the normal distribution shown below?

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?

What is the mean of the normal distribution shown below?

The lengths of a lawn mower part are approximately normally distributed with a given mean = 4 in. and standard deviation = 0.2 in. What percentage of the parts will have lengths between 3.8 in. and 4.2 in.?

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 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?