Chapter 11 (Triola)

Contingency tables - test for independence

Calculator (TI-82) help for calculation of the test statistic.

(This works for the TI-83/84 also, but that calculator has its own, better technique using matrices.
See your text book)

EXAMPLE:
 

embezzlement fraud  forgery 
sent to jail 22

(33.97)

130

(118.68)

20

(19.35

172
not sent to jail 57

(45.03

146

(157.32)

25

(25.65)

228

79 276 45 400

1. Put the observed values in list L1.

2. Put the expected values in list L2. These are the values in the table in parentheses. The calculation

  for the expected values is E = (row total)(column total)/(grand total).

3. Calculate the test statistic (chi - square) as follows:

  sum((L1 - L2)^2/L2)

  where "sum" is found in 2nd List MATH menu

4. The test statistic for the above example is:

  (chi-square) = 9.3323