Introduction
Grouped data are presented in frequency distributions rather than entering each observation individually. Given a set of data points:
X 1, X 2, . . . , X n,
with respective frequencies:
f 1, f 2, . . . , f n,
this procedure computes the mean, standard deviation, and standard error of the mean.
Instructions
Follow these steps to compute the mean, standard deviation, and standard error of the mean:
- Press f, then CLEAR [ REG].
- Key in the first value and press ENTER twice.
- Key in the respective frequency and press STO, [ +], 0, [ X], then Sigma +. The display shows the number of data points entered.
- Repeat steps 2 and 3 for each data point.
- To calculate the mean (average) press RCL, 0, STO, 1, RCL, 6, STO, 3, g, then x-mean (the zero key).
- Press g, then s to find the standard deviation
- Press RCL, 0, g, the Square Root key, then the Divide key to find the standard error of the mean.
Example
A survey of 266 one-bedroom apartment rentals reveals that 54 rent for $190 per month, 32 rent for $195 per month, 88 rent for $200 per month, and 92 rent for $206 per month. What are the average monthly rental, the standard deviation, and the standard error of the mean?
Keystrokes
Display
Comments
f, CLEAR [ REG], 190, ENTER, ENTER, 54, STO, [ +], 0, [ X],then Sigma +
1.00
Calculator cleared and first data point entered
195, ENTER, ENTER, 32, STO, [ +], 0, [ X], then Sigma +
2.00
Second data point entered
200, ENTER, ENTER, 88, STO, [ +], 0, [ X], then Sigma +
3.00
Third data point entered
206, ENTER, ENTER, 92, STO, [ +], 0, [ X], then Sigma +
4.00
Fourth data point entered
RCL, 0, STO, 1, RCL, 6, STO, 3, g, then x-mean
199.44
Average monthly rent.
g, then s
5.97
Standard Deviation
RCL, 0, g, square root, then divide
0.37
Standard Error of the mean