Question

For a normal distribution, what percentage of values lies within two standard deviations of the mean?

Answer 1

The answer is indeed D. If you check the normal distribution curve you get that within 1 standard diviation its
34%+34%=68%
Within 2 it's 34+34+13.5+13.5= 95%
And within 3 it's 34+34+13.5+13.5+2.5+2.5=100%