Question

A sample of men's ages at first marriage is below.

26	31	29	27	30	28	27	31	23
29	29	30	32	28	30	28	29	35

a) Calculate x¯_______ and_______ s to 03 decimal places.

x¯= and s=

b) Calculate the intervals x¯±s,  x¯±2s, and x¯±3s using the values from a).

x¯±s= _______to _________

x¯±2s= ________to _________

x¯±3s= _______to ________

c) What proportion of values fall within each interval? How does this compare to the Empirical Guidelines?

Round your answers to the nearest percent.

___________% of the values are within one standard deviation of the mean. The Empirical Guidelines suggest that about ______% of the data should be within that area.

________% of the values are within two standard deviations of the mean. The Empirical Guidelines suggest that about ________% of the data should be within that area.

_________% of the values are within three standard deviations of the mean. The Empirical Guidelines suggest that about __________% of the data should be within that area.

Answer 1

a)x=29.133 and s=2.748

b)

c) here n=18

number of values between m+sd is 15

probability = 15/18=0.83=83%

16 values are between m+2sd

probability = 16/18 = 0.88=88%

17 values are between m+3sd

probability = 17/18 = 0.94=94%