SOLUTION: Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 76 people in the 18-21 age bracket and finds that 65 of them r

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Question 1200237: Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 76 people in the 18-21 age bracket and finds that 65 of them respond and 11 refuse to respond. When 296 people in the 22-29 age bracket are contacted, 263 respond and 33 refuse to respond. Assume that 1 of the 372 people is randomly selected. Find the probability of getting someone in the 18-21 age bracket or someone who responds.
Report the answer as a percent rounded to one decimal place accuracy. You need not enter the "%" symbol.
P(18-21 or responds) =
%
(Hint: It might be helpful to organize the data into a table first.)
Answer by math_tutor2020(3817) About Me  (Show Source):
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This is one way to write out the data table.
Age 18-21Age 22-29Total
Responds65263328
Refuse to Respond113344
Total76296372

Define these events:
A = person is in the 18-21 age bracket
B = person responds

n(A) = number of people in the 18-21 age bracket
n(A) = 76
n(B) = 328
n(A and B) = 65
These values are found in the table above.

Use those values to compute the following.
n(A or B) = n(A) + n(B) - n(A and B)
n(A or B) = 76 + 328 - 65
n(A or B) = 339
There are 339 individuals who are either in the 18-21 age bracket, have responded, or both.

P(A or B) = n(A or B)/n(total)
P(A or B) = 339/372
P(A or B) = 0.911290322580645 approximately
P(A or B) = 0.911
P(A or B) = 91.1%


Answer: 91.1%