Question

1. A group of people were asked if they had run a red light in the last year. 380 responded "yes", and 328 responded "no".

Find the probability that if a person is chosen at random, they have run a red light in the last year.

Give your answer as a fraction or decimal

2. Giving a test to a group of students, the grades and gender are summarized below

A B C Total

Male 19 6 12 37

Female 7 15 11 33

Total 26 21 23 70

Let

X

X

be the event that the student got an A

If one student was chosen at random, find P(

X

X

).

Hint: 'Find P(

X

X

)' means find the probability that the student got an A

P(XX)=   

Give your answer rounded to 4 decimals.

3.A poll showed that 43.6% of Americans say they believe that statistics teachers know the true meaning of life. What is the probability of randomly selecting someone who does not believe that statistics teachers know the true meaning of life.

Report the answer as a percent rounded to one decimal place accuracy. You need not enter the "%" symbol.

prob = %

4.In a study of brand recognition, 1188 consumers knew of Amazon, and 4 did not. Use these results to estimate the probability that a randomly selected consumer will recognize Amazon.

Report the answer as a percent rounded to one decimal place accuracy. You need not enter the "%" symbol.

prob = %

5. Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 80 people in the 18-21 age bracket and finds that 68 of them respond and 12 refuse to respond. When 282 people in the 22-29 age bracket are contacted, 254 respond and 28 refuse to respond. Assume that 1 of the 362 people is randomly selected. Find the probability of getting someone in the 22-29 age bracket or someone who agreed to respond.

Give your answer as a decimal (to at least 4 places).

Answer 1

(1)

The probability that if a person is chosen at random, they have run a red light in the last year is given by:

(2)

P(X) = P( the student got an A) is given by:

(3)

The probability of randomly selecting someone who does not believe that statistics teachers know the true meaning of life is given by:

100 - 43.6 = 56.4   %

(4)

The probability that a randomly selected consumer will recognize Amazon is given by:

%

(5)

The probability of getting someone in the 22-29 age bracket or someone who agreed to respond is given by: