In: Statistics and Probability
n a recent poll, a random sample of adults in some country (18 years and older) was asked, "When you see an ad emphasizing that a product is "Made in our country," are you more likely to buy it, less likely to buy it, or neither more nor less likely to buy it?" The results of the survey, by age group, are presented in the following contingency table. Complete parts (a) through (c).
Purchase likelihood |
18 dash 3418-34 |
35 dash 4435-44 |
45 dash 5445-54 |
55 plus55+ |
Total |
|
---|---|---|---|---|---|---|
More likelyMore likely |
227227 |
358358 |
371371 |
400400 |
13561356 |
|
Less likelyLess likely |
2929 |
66 |
2222 |
1212 |
6969 |
|
Neither more nor less likelyNeither more nor less likely |
281281 |
203203 |
167167 |
112112 |
763763 |
|
Total |
537537 |
567567 |
560560 |
524524 |
21882188 |
(a) What is the probability that a randomly selected individual is
35 to 4435 to 44
years of age, given the individual is
more likelymore likely
to buy a product emphasized as "Made in our country"?The probability is approximately
nothing.
(Round to three decimal places as needed.)
Solution:
Given:
Numbers given in tables are repeated in each cell. So I have reconstructed table as below:
"When you see an ad emphasizing that a product is "Made in our country," are you more likely to buy it, less likely to buy it, or neither more nor less likely to buy it?"
Purchase likelihood | 18-34 | 35-44 | 45-54 | 55+ | Total |
More likely | 227 | 358 | 371 | 400 | 1356 |
Less likely | 29 | 6 | 22 | 12 | 69 |
Neither more nor less likely | 281 | 203 | 167 | 112 | 763 |
Total | 537 | 567 | 560 | 524 | 2188 |
Part a) Find the probability that a randomly selected individual is 35 to 44 years of age, given the individual is more likely to buy a product emphasized as "Made in our country".
Let A : individual is 35 to 44 years of age and
B : the individual is more likely to buy a product emphasized as "Made in our country"
So we have to find : P( A given B) =........?
That is:
P(A | B) = ............?
We use conditional probability formula to find above probability:
where
P(A and B) = Number of individual is 35 to 44 years of age as well as is more likely to buy a product / N
P(A and B) = 358 / 2188
and
P(B) =Number of individual is more likely to buy a product emphasized as "Made in our country" / N
P(B) = 1356 / 2188
Thus
Thus the probability that a randomly selected individual is 35 to 44 years of age, given the individual is more likely to buy a product emphasized as "Made in our country" is : 0.264