Question

The mean of a normal probability distribution is 400; the standard deviation is 15. a. About 68% of the observations lie between what two values? Lower Value Upper Value b. About 95% of the observations lie between what two values? Lower Value Upper Value c. Nearly all of the observations lie between what two values? Lower Value Upper Value

statisyics

Answer 1

According to the empirical rule, approximately 68%, 95% and 99.73% observations lie within one, two and three standard deviations from the mean respectively.

a)

So, about 68% observation lie in the interval:

b)

So, about 95% observation lie in the interval:

c)

So, about 99.73% i.e. nearly all observation lie in the interval: