A sample of 500 evening students revealed that their annual incomes from employment in industry during the day were normally distributed with a mean income of $30,000 and a standard deviation of $3,000. (i) 250 students earned more than $30,000.
(ii. 500 students earned between $20,000 and $40,000.
(iii) 6 students earned less than $22,500.
A) (i), (ii), and (iii) are all correct statements
B) (i) is a correct statement but not (ii) or (iii).
C) (i) and (iii) are correct statements but not (ii).
D) (i) and (ii) are correct statements but not (iii).
E) (ii) and (iii) are correct statements but not (i).

Question

Quizplus · Accepted Answer

(i) is correct because it is given that the mean income is $30,000 and 250 students earned more than that. 
(ii) is also correct because the income range of $20,000 to $40,000 includes the mean income of $30,000 within its range. 
(iii) is not correct because we are given that only 6 students earned less than $22,500, which is a very small percentage of the total sample size of 500 students.

A Sample of 500 Evening Students Revealed That Their Annual