Review Quiz 5.5-5.7

What is the mean and standard deviation of this normal distribution?

• $\mu=65;\ \sigma\ =\ 10.5$

• $\mu=54.5;\ \sigma=3.5$
  

• $\mu=65;\ \sigma=3.5$

• $\mu=65;\ \sigma=21\$

Suppose heights of 9 year old girls are normally distributed with a mean of 52 inches and a standard deviation of 2 inches. About what percent of 9 year old girls are between 50 and 54 inches tall?

• 60%

• 68%

• 76%

• 84%

X is normally distributed with a mean of 80 and a SD of 5. Find P(X < 82).

• .6832

• .6437

• .3446

• .6554

Suppose the lengths of a certain fish are normally distributed with mean=9 inches and standard deviation=1.2 inches. Only fish that are 10 inches or longer may be kept. Others must be thrown back. What proportion of fish can be kept?

• .2023

• .2425

• .3198

• .7977

Write the probability statement for the graph.

• P(x < 5.6)

• P(x > 2.9)

• P(x < 2.9 or x > 5.6)

• P(2.9 < x < 5.6)

Suppose student GPAs are normally distributed with a mean of 84.1 and standard deviation of 6.8. What GPA would be the boundary for the top (right tail) 5%?

• 95.285

• 72.915

• 90.9

• 97.725

Heights for 11 year old females are normally distributed with a mean of 56.7 inches and a standard deviation of 2.1 inches. The doctor says my 11 year old is at the 70th percentile of heights. How tall is she?

• 58.8 inches

• 58.2 inches

• 57.8 inches

• 55.6 inches

Which of the following is not a continuous random variable?

• The head circumferences of all BISD 3rd graders.

• The amount of calories consumed at lunch by HHS students.

• The amount of water consumed by HHS students in a day.

• The number of classes failed by HHS students during the first semester.

Some normal distributions are skewed in shape.

• True

• False

Which of the following is the correct mean and standard deviation for the standard normal (Z) distribution?