Casio fx-570MS - Manual (Page 31)

– 28 –
Statistics Problems
Example 1 Example 1
The following are the measured 100-meter race times for five students.
12.5 11.6 10.8 12.8 11.4 (Unit: Seconds)
Calculate the mean and the sample standard deviation for these results.
Replace the times of the 12-second runners (runner 1 and runner 4) with
11.1 and 11.7 seconds (which are times run by other students), and
calculate the mean and sample standard deviation again.
Sample standard deviation is a value that expresses
the level of variation among data.
When the number of data samples is n , the value of each
data is x
i
( i = 1... n ), and the mean is x :
Sample standard deviation
σ
n- 1
=
(Σ
x
i
2 – n x 2 )/(n–
1
) .
Instead of using these complex formulas, you can obtain the same
results using a simple key operation on the calculator.
*The following shows operation using the fx-82MS/85MS/350MS/95MS.
1 .
Enter the SD Mode, and clear the statistical memory area.
F 2
A B 1
(Scl) =
2 .
Input the data.
In the SD Mode, the | key operates as the S key.
Input a value and then press the
S
key to register it.
To input two sequential values that are identical, input the value and then press S twice. .
The display shows how many values have been input (number of samples = n).
12.5 S 11.6 S 10.8 S 12.8 S 11.4 S
3 .
Calculate the mean of the data.
t A X 1 =
Explanation Explanation
Operation
12.5
11.6
10.8
12.8
11.4