APPENDIX 1
Critical values for correlation coefficients

Critical r			Critical r
df	P = 0.05	P = 0.01	df	P = 0.05	P = 0.01
1	0.997	1.000	19	0.433	0.549
2	0.950	0.990	20	0.423	0.537
3	0.878	0.959	25	0.381	0.487
4	0.811	0.917	30	0.349	0.449
5	0.754	0.874	40	0.304	0.393
6	0.707	0.834	50	0.273	0.354
7	0.666	0.798	60	0.250	0.325
8	0.632	0.765	70	0.232	0.302
9	0.602	0.735	80	0.217	0.283
10	0.576	0.708	90	0.205	0.267
11	0.553	0.684	100	0.195	0.254
12	0.532	0.661	125	0.174	0.228
13	0.514	0.641	150	0.159	0.208
14	0.497	0.623	200	0.138	0.181
15	0.482	0.606	300	0.113	0.148
16	0.468	0.590	400	0.098	0.128
17	0.456	0.575	500	0.088	0.115
18	0.444	0.561	1 000	0.062	0.081

df (= “degrees of freedom”) is equal to the number of observations (data pairs) minus two (thus df = n-2)

P = 0.05 and P = 0.01 refer to the probability of 5 and 1 percent, respectively, that the correlation, although “significant” is still the result of chance

APPENDIX 1 Critical values for correlation coefficients

APPENDIX 1
Critical values for correlation coefficients