1

Matched pairs t-tests

• Paired observations reduced independence of observations

• Matched pairs t-test

(x11, x12, …, x1n)

(x21, x22, …, x2n)

2

Matched Pairs t-tests

ttest =| d

sd

n

(di - d)2

n - 1Sd =

3

Source: http://cdiac.ornl.gov/epubs/ndp/ushcn/state_NC_mon.html

4

Source: http://cdiac.ornl.gov/epubs/ndp/ushcn/state_NC_mon.html

5

2001 is significantly drier than 2000 in central North Carolina.