Numbers of cricket chirps in 15 seconds:
20
16
20
18
17
16
15
17
15
16
15
17
16
17
14

Temperatures in degrees Farenheit when the chirps were counted:
89
72
93
84
81
75
70
82
69
83
80
83
81
84
76

This data is taken from "key problem 1", a web page made available by
the Office for Mathematics, Science, and Technology Education at the
University of Illinois at Urbana/Champaign.  It is retyped here for
ease in entering into a spreadsheet. See their website, 
http://www.mste.uiuc.edu, for other interesting things.