Question

The mean of a normal probability distribution is 360; the standard deviation is 14.

  

(a)	About 68 percent of the observations lie between what two values?

  

Value 1
Value 2

  

(b)	About 95 percent of the observations lie between what two values?

  

Value 1
Value 2

  

(c)	Practically all of the observations lie between what two values?

  

Value 1
Value 2

  

Answer 1

(a)

By Empirical Rule:

68% of data will lie in mean Standard deviation

= 360 14 = (346, 374)

So,

Answer is:

Value 1	346
Value 2	374

(b)

By Empirical Rule:

95% of data will lie in mean 2 X Standard deviation

= 360 ( 2 X 14) = 360 28 = (332, 388)

So,

Answer is:

Value 1	332
Value 2	388

(c)

By Empirical Rule:

Practically all of observations will lie in mean 3 X Standard deviation

= 360 ( 3 X 14) = 360 42 = (318, 402)

So,

Answer is:

Value 1	318
Value 2	402