Distribution Problems

A continuous random variable is normally distributed with mean 145 and standard deviation is 5. Find P(136<X<140).

• 0.8054

• 0.8772

• 0.1228

• 0.1587

What shape is a normal distribution curve?

• Half curve

• Round curve

• Bell curve

• Square curve

What is the the total area under the standard normal distribution curve?

• 100

• 25

• .5

• 1

Which is NOT true about the normal distribution curve?

• It is bell-shaped.

• The mean, median, and mode are approximately equal

• The smaller the standard deviation, the less spread in the curve.

• It is asymmetrical.

The following table represents the probability distribution X, the employment status of adults in a city. What is the probability that the adults isn't retired?

The following table represents the probability distribution X, the employment status of adults in a city.

What is the probability that the adults isn't retired?

According to the empirical rule, what percentage of data falls within 1 standard deviation? 

• 25%

• 68%

• 95%

• 99.7%

According to the empirical rule, how much of the data falls within 3 standard deviations? 

• 25%

• 68%

• 95%

• 99.7%

Which best describes the shaded part of this normal distribution graph?

• All data that is one or higher.

• All data that is one or more standard deviations above the mean.

• All data that is between 1 and 3.

• All data that is above the mean.

The mean GPA of students in a course at UCDavis is 3.2 with a standard deviation of 0.3. What percent of students in the course have a GPA between  2.9 and 3.8? 

• 81.5%

• 47.5%

• 68%

• 95%