Table 7. Correlation coefficients between repeated

tests at Cambridge, excluding PV-1 and CC/1

	27 Oct	29 Nov	17 Dec
12 Oct	0.48	0.44	0.80**
27 Oct	-------	0.53	0.47
29 Nov		-------	0.79 *
Mean	0.59**

*, ** significant at P = 0.5, 0.05 respectively