M is a certain set of numbers with an average (arithmetic mean) of 10 and a standard deviation of 1. Q is a subset of M consisting of 5 terms. Exactly 80% of the numbers in Q are located within 2 standard deviations from the average of M. Which of the following could Q be? Choose the correct choice.
A) {3, 4, 5, 10, 14} B) {3, 6, 7, 10, 12} C) {3, 5, 5, 10, 16} D) {1, 5, 7, 10, 12} E) {5, 8, 9, 10, 12}
Exactly 80% of the numbers in Q, so 4 out of 5 numbers are from 10 - 2*{SD} = 8 to 10 + 2*{SD} = 12.   A. {3, 4,5, 10, 14} --&gt; only 1 number is in this range. Discard.   B. {3,6, 7, 10, 12} --&gt; only 2 numbers are in this range. Discard.   C. {3,5, 5, 10, 16} --&gt; only 1 number is in this range. Discard.   D. {1,5, 7, 10, 12} --&gt; only 2 numbers are in this range. Discard.   E. {5, 8, 9, 10, 12} --&gt; 4 numbers are in this range. OK.   Answer:{5, 8, 9, 10, 12}.
<result>E</result>
M is a certain set of numbers with an average (arithmetic mean) of 10 and a standard deviation of 1. Q is a subset of M consisting of 5 terms. Exactly 80% of the numbers in Q are located within 2 standard deviations from the average of M. Which of the following could Q be?