Question

The mean of a normal probability distribution is 410; the standard deviation is 105. a. μ ± 1σ of the observations lie between what two values? Lower Value Upper Value b. μ ± 2σ of the observations lie between what two values? Lower Value Upper Value c. μ ± 3σ of the observations lie between what two values? Lower Value Upper Value

Answer 1

a)

1 of the observations lie between - 1 and + 1

That is

between 410 - 1 * 105 and 410 + 1 * 105

Between 305 and 515

Lower value = 305

Upper value = 515

b)

2 of the observations lie between - 2 and + 2

That is

between 410 - 2 * 105 and 410 + 2 * 105

Between 200 and 6

20

Lower value = 200

Upper value = 620

c)

3 of the observations lie between - 3 and + 3

That is

between 410 - 3 * 105 and 410 + 3 * 105

Between 95 and 725

Lower value = 95

Upper value = 725