HP 12C#ABA hp 12c_solutions handbook_English_E.pdf - Page 112

Number, Observed Frequency, Keystrokes, Display

Page 112 highlights

n ∑ x2 = (---O----i--E-----i--E----i-)- i=1 If there is a close agreement between the observed and expected frequencies, x2 will be small. If the agreement is poor, x2 will be large. The following keystrokes calculate the x2 statistic: 1. Press CLEAR . 2. Key in the first Oi value and press . 3. Key in the first Ei value and press 0 0 . 4. Repeat steps 2 and 3 for all data pairs. The x2 value is displayed. 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 1 2 3 4 5 6 Observed Frequency 25 17 15 23 24 16 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 R0 each time.) Keystrokes Display CLEAR 25 1.25 20 0 0 17 20 1.70 0 111

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111
If there is a close agreement between the observed and expected
frequencies,
x
2
will be small. If the agreement is poor,
x
2
will be large.
The following keystrokes calculate the
x
2
statistic:
1.
Press
CLEAR
.
2.
Key in the first
O
i
value and press
.
3.
Key in the first
E
i
value and press
0
0
.
4.
Repeat steps 2 and 3 for all data pairs. The
x
2
value is displayed.
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.
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
0
each time.)
Number
1
2
3
4
5
6
Observed Frequency
25
17
15
23
24
16
Keystrokes
Display
CLEAR
25
20
0
0
1.25
17
20
0
1.70
x
2
O
i
E
i
(
)
E
i
---------------------
i
1
=
n
=