What proportion of values in a normal distribution will be in an interval that starts at 2.0 standard deviations to the left of (or below) the mean and extends to 1.0 standard deviation to the right of (or above) the mean?
A).7157
B).8365
C).8185
D).9162
E).8925

Question

Quizplus · Accepted Answer

The area under the normal distribution curve between -2.0 and +1.0 standard deviations from the mean is approximately 81.85% (or 0.8185). This is found by adding the area from the mean to -2 standard deviations (approximately 47.72%) to the area from the mean to +1 standard deviation (approximately 34.13%).

What Proportion of Values in a Normal Distribution Will Be