Formulas
Chi Square
Chi Square Tables
Reliability / Validity
100
Play the video from 1:00-1:10.
Use the formula to determine df.
df = (R-1)(C-1) = (4-1)(2-1) = (3)(1) = 3
100
What is the difference between the three below?
X squared
chai tea
chi squared
100
Part a. List the observed frequencies.
Part b. State N.
a. 23, 6, 1, 23
b. N = 53
100
This is the formula for predictive validity / explained variance as a percent.
r2x100
200
Formula for fe
200
What do fo and fe stand for?
observed frequency & expected frequency
200
What is the difference between obtained chi square and critical chi square?
obtained chi square is the value calculated based on the data
critical chi square is a cut-off value on a chart used to determine significance
200
A personality test is designed to determine how well two people match romantically. r = 0.7. What is the predictive validity / explained variance as a percent?
49
300
draw a chi square matrix for which df would not equal 1
Any matrix other than 2 x 2
300
10 students were drinking Chai tea while solving chi square problems. All 4 students with glasses solved the problem correctly and all 6 students without glasses solved the problem incorrectly. Is wearing glasses related to the ability to solve a chi square problem?
Yes
300
If p = .04, the confidence level is ___%. Fill in the blank AND state whether the variables are or are not significantly related.
96% and significantly related
300
Mr. Serling puts an Anatomy question on his final exam. His exam could be criticized because it is considered not ____. Use an appropriate Statistics term to fill in the blank.
valid
400
Formula for obtained chi squared (not the 2 x 2 shortcut formula)
400
In a chi square matrix, the row totals are 10 & 15 and the column totals are 12 & 13. What is N?
25
400
What p-value indicates 99% confidence?
p = .01
400
The October and November SATs are designed to be equally difficult so that student scores are consistent. The SAT does a poor job predicting what it is designed to: first year college grades. Based on this information, is the SAT reliable, valid, both or neither?
reliable
500
Chi square by hand shortcut formula for 2 X 2 matrix
500
The observed and expected frequencies are equal. Determine the numerical value of obtained chi square.
0
500
Draw a chi square matrix for which the df = 6.
500
The predictive validity / explained variance between two variables is 64%. List the possible value(s) of r.
0.8 and -0.8