Matched Pairs Test
Section 11.2
Sodoku Anyone?
*I need some people who have never
played…
*Let’s see if boys are better than girls….
Are Boys Better than Girls?
Newbies…Do your scores increase if I
explain how it’s scored?
Matched Pairs T-Test

Matching subjects according to a
characteristic for blocking purposes.

Can be paired in before/after

Screens out extraneous factors.

Inferences can be based on the
differences between the 2
observations in each sample pair.
Parameter of Interest
d  1  2
Assumptions
Dependent (Paired) Random samples
 Approximately normal


Use boxplot to show this
• (only 1 – of the list of differences)
Test Statistic
x  d
t
sd
n
An educator claims that a special vitamin will increase a weight
lifter’s strength. Eight weight lifters are selected and given a test
and are tested again 2 weeks after the vitamin use.
Athelete
1
2
3
4
5
6
7
8
Before
210
230
182
205
262
253
219
216
After
219
236
179
204
270
250
222
216
Confidence Interval
 sd 
xd  t 

 n
A dietitian wishes to see if a person’s cholesterol level will
change if the diet is supplemented by a mineral. Can it be
concluded that the cholesterol level has changed. Construct
a 90% confidence interval.
Subject
1
2
3
4
5
6
Before
210
235
208
190
172
244
After
190
170
210
188
173
228
Homework

Worksheet