The mean of a normally distributed dataset is 12, and the standard deviation is 2.
what ? % of the data points lies between 8 and 16.

In the Normal distribution: if the mean (M) is 12 and the standard deviation (s)is 2, then between 8 (12- 2*2, or M - 2 s) and 16 (12 + 2*2, or M+2 s ),or between M - 2 s and M + 2 s lies 13.6 %+ 34.1% + 34.1 % + 13.6% = 95.4% data points. Graph is in the attachment.