Question

You want to find the standard deviation of the internal body temperatures of a group of healthy adults. Here are the temperatures, in degrees Fahrenheit:

99.2   98.9   98.2   97.3   98.9   98.4   97.2   99.1

Find the mean of this data set: Answer?

Now, use the mean to find the deviation for each score. The deviation is the score minus the mean.

Data Value	Deviation = Data Value - Mean
99.2	Answer?
98.9	Answer?
98.2	Answer?
97.3	Answer?
98.9	Answer?
98.4	Answer?
97.2	Answer?
99.1	Answer?

What is the sum of all the deviations? Answer?

Answer 1

Mean=(99.2+ 98.9+98.2+97.3+98.9 +98.4+97.2+99.1)/8

Mean=787.2/8

mean of this data set=98.4

Data value	Deviation=Data value -mean	Deviation ^2
99.2	99.2-98.4=0.8	0.64
98.9	98.9-98.4=0.5	0.25
98.2	98.2-98.4=-0.2	0.04
97.3	97.3-98.4=-1.1	1.21
98.9	98.9-98.4=0.5	0.25
98.4	98.4-98.4=0	0
97.2	97.2-98.4=-1.2	1.44
99.1	99.1-98.4=0.7	0.49
	Sum=0	4.32

Sum of deviation=0.8+0.5-0.2-1.1+0.5+0-1.2+0.7=0 d

Population std deviation deviation=Sqrt(sum(Data value-mean)²/n)=Sqrt(4.32/8)=0.734847

Sample deviation deviation=Sqrt(sum(Data value-mean)²/n-1) =sqrt(4.32/7)=0.7855