Math 4 Unit 6

The mean life of a tire is 30,000 km. The standard deviation is 2000 km.

Then, 68% of all tires will have a life between ___________ km and __________ km.

•  28,000 km and 32,000 km.
• 24,000 km and 34,000 km.
• 26,000 km and 34,000 km.
• 27,000 km and 31,000 km.

At a local high school, GPA's are normally distributed with a mean of 2.9 and standard deviation of 0.6. What is the GPA of the highest 2.5% of the students?

• 4.1 
• 4.1 or higher
• 4.7
• 4.5 or higher

In a normal distribution, what percent of the values lie within one standard deviation of the mean?

(from z = -1 to z = 1)

• 13.5%

• 34%

• 95%

• 68%

In a normal distribution, what percent of the values lie above the mean?

• 13.5%

• 34%

• 50%

• 68%

You roll a standard die. You win $12 if you roll a six, $6 if you roll a one, and $0 if you roll anything else. What is the expected value of a single roll?

• $3

• $18

• $9

• $2

An automobile dealer decides to select a month for its annual sale.  Find the probability that it will be September or October.

• 1/12
• 1/6
• 1/4
• 5/6

At a community swimming pool there are 2 managers, 8 lifeguards, 3 concession stand clerks, and 2 maintenance people.  If a person is selected at random, find the probability that the person is either a lifeguard or a manager.

• 2/3
• 8/15
• 2/15
• not enough information

You have a bag of 17 marbles.  Four are blue, 6 are green, 2 are red, and the others are yellow.  What is the probability of drawing a green marble, putting it aside, and then drawing another green marble?

• 15/136
• 30/289
• Other

A bag contains 5 blue marbles, 4 red marbles, and 3 orange marbles. Mrs. Cox picks one without looking, replaces it and picks another one. What is the probability that she picks two that are not orange? 

• 9/16
• 3/4
• 9/144
• 5/16

What does the n stand for in the binomial probability formula?

• Number of trials
• Number of Successes
• Probability of Successes
• Probability of Failures