HW 10.3 Probability Distributions

A marketing survey compiled data on the number of cars in households.  If X = the number of cars in a randomly selected household, and we omit the rare cases of more than 5 cars, then X has the following probability distribution: 
X           0          1          2          3           4           5    
P(X)   0.24    0.37    0.20    0.11    0.05     0.03
What is the probability that a randomly chosen household has at least two cars?

• 0.20
• 0.29
• 0.39
• 0.61

1. The human resources managers at a company records the length, in hours, of one shift at work, x. He creates the probability distribution below. What is the probability that a worker chosen at random works at least 8 hours?

• 0.62

• 0.78

• 0.84

• 0.96

Is this a probability distribution?

• No, the sum of p(x) does not equal 1.

• Yes, all p(x) are between 0 and 1.

• No, all p(x) are not between 0 and 1.

• Yes, the sum p(x) is 1.

Find the missing value for P(X=5) in the probability ditribution:

Number of Toys | Probability

0| 0.03

1| 0.16

2| 0.30

3| 0.23

4| 0.17

5| ?

• 0.11

• 0.21

• 0.01

• 0.31

The table represents the probability of guessing correct on a 5 question true-false quiz. Find the probability all 5 questions correct.

• .03125

• .15625

• .3125

• .1875

The table represents the probability of guessing correct on a 5 question true-false quiz.  Find the probability for at least 4 questions correct.

• .03125
• .15625
• .3125
• .1875

A manager records the number of hours, x, worked each shift by each employee and develops a distribution table. One hundred people work for the manager. How many people work 4 hours per shift?

• 0.4

• 0.04

• 0.14

• 0.17