Introduction to Normal Distributions — Quiz Answers

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

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

The heights of a certain type of tree are approximately normally distributed with a mean height mu is equal to 5 ft and a standard deviation sigma is equal to 0 point 4 ft. Which statement must be true?

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

The amount of daily time that teenagers spend on a brand A cell phone is normally distributed with a given mean mu is equal to 2 point 5 hr and standard deviation sigma is equal to 0 point 6 hr. What percentage of the teenagers spend more than 3 point 1 hr?

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

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 times of all 15 year olds who run a certain race are approximately normally distributed with a given mean mu is equal to 18 sec and standard deviation sigma is equal to 1 point 2 sec. What percentage of the runners have times less than 14 point 4 sec?

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

The lengths of a lawn mower part are approximately normally distributed with a given mean mu is equal to 4 in. and standard deviation sigma is equal to 0 point 2 in. What percentage of the parts will have lengths between 3 point 8 in. and 4 point 2 in.?