Prob Stat Review

A farm has 5 brown cows and 10 white cows. A fence is open and two cows escape. What is the probability that it will be a brown cow, then a white cow?

• 5/15 + 10/14

• 5/15 x 4/15

• 5/15 x 10/14

• 5/15 x 10/15

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days.

About what percent of the products last between 12 and 15 days?

• 68%

• 34%

• 16%

• 2.5%

Calculate the z score of your value if the mean is 75, your score is 90 and the standard deviation is 4.5

• -3.33

• 3.33

• 0.78

• -0.78

If heights of 3rd graders follow a normal distribution with a mean of 52 inches and a standard deviation of 2.5 inches, what percent of 3rd graders are less than 50 inches tall?

• About 50%

• About 21%

• About 79%

• About 14%

Find the z-score.

Mean = 38

Standard Deviation: 1.2

x = 42

• 3.33

• -3

• 3.03

• -3.33

Scores on a certain standardized test have a mean of 500, and a standard deviation of 100. What score would you need to fall at the 84th percentile?

• 84

• 400

• 500

• 600

A 12 oz. can of soda has a mean volume of 12 oz, with a standard deviation of 0.25 oz. What is the percentile for a soda that only has 11.5 oz.?

• 3rd percentile

• 16th percentile

• 50th percentile

• 84th percentile

How many students received a score in the 80's?

• 2

• 10

• 14

• 27

What percentage of girls have blonde hair?

• 30%

• 32%

• 29%

• 40%

Which of the following shows how to determine P(even number or a factor of 6)?

• 3/6 + 4/8 - 1/2

• 4/8 + 4/8 - 2/8

• 4/8 + 2/8 - 4/8

• 5/8 + 4/8 - 1/8