Bunuel wrote:
500 records have a distribution that is symmetric about the mean 10. If 68 percent of the distribution lies within one standard deviation of the mean, and the deviation is 2, then at least how many of the records are less than 12?
(A)160
(B)320
(C)340
(D)420
(E)460
Mean = 10 ; Deviation = 2. Therefore value pair of standard deviation = 8,12.
68% lies between value 8 and 12. And 16% less than 8.
Therefore, total 84% less than 12.
84% of 500 = 420.
Option D.
...
.jpg)
