HP 12c Solutions Handbook page 112

If there is a close agreement between the observed and expected
2
frequencies, x will be small. If the agreement is poor, x
The following keystrokes calculate the x
1. Press
2. Key in the first O
3. Key in the first E
.
4. Repeat steps 2 and 3 for all data pairs. The x
Example 1: A suspect die from a Las Vegas casino is brought to an
independent testing firm to determine its bias, if any. The die is tossed 120
times and the following results obtained.
Number
Observed Frequency
The expected frequency = 120 throws / 6 sides, or E = 20 for each
number, 1 thru 6. (Since E is a constant in this example, there is no need
to store it in R each time.)
0
Keystrokes
CLEAR
25
20 0
0
17 20
2
x =
CLEAR .
value and press
i
value and press
i
1.25
1.70
0
n
∑
O – E
i i
-------------------- -
E
i
i = 1
2
statistic:
.
0
1 2 3
25 17 15
Display
111
2
will be large.
2
value is displayed.
4 5
23 24
0
6
16