Exhibit 4-1.Two hundred people were asked if they had read a book in the last month.The accompanying contingency table,cross-classified by age,is produced. Refer to Exhibit 4-1.Given that a respondent read a book in the last month,the probability that he/she is at least 30 years old is closest to ________.
A)0.33
B)0.46
C)0.65
D)0.88

Question

Exhibit 4-1.Two hundred people were asked if they had read a book in the last month.The accompanying contingency table,cross-classified by age,is produced.  Refer to Exhibit 4-1.Given that a respondent read a book in the last month,the probability that he/she is at least 30 years old is closest to ________.
A)0.33 
B)0.46 
C)0.65 
D)0.88

Quizplus · Accepted Answer

To find the probability that a respondent is at least 30 years old given that they have read a book in the last month, we need to identify the relevant cell in the contingency table. The cell that represents people who have read a book in the last month and are at least 30 years old is 60. To find the probability, we divide this cell by the total number of people who have read a book in the last month, which is 120. So, the probability is 60/120 = 0.5. Therefore, the closest answer choice is B (0.46).