Example: Calculating the Mean and Standard
Deviation. Production supervisor May Kitt wants to determine how
long a certain process takes. She randomly picks six people, observes
them as they carry out the process, and records the number of min-
Calculate the mean and standard deviation of the times.
1 2:+ I
1 STAT I
1 STAT I
Clears the statistical
Enters the first time.
Enters the remaining
Calculates the mean.
Calculates the standard
Calculating the Population Standard Deviation
The standard deviations calculated by
are the sam-
ple standard deviations. They assume that the data is a samplipg of a
larger, complete set of data. If the data constitutes the entire popula-
tion of data, the
true population standard deviation
can be computed by
calculating the mean of the original data, adding the mean to the sta-
tistical data using
and then calculating the standard deviation.
5: Statistical Calculations