Table 2.

Statistical analysis of TSE incubation period

Inoculum	Route	Variance ratio (within controls)	% Difference in incubation period (floxed PrP vs controls)	Variance ratio (Schwann cell PrPknock-out vs controls)	% Difference in incubation period (Schwann cell PrP knock-out vs controls)
139A	Intracerebral	0.66ns	+1.52	5.50*	+4.09
139A	Intraperitoneal	3.22*	−14.89	9.31**	+15.84
139A	Oral	0.46ns	+5.94	0.78ns	−5.65
ME7	Intracerebral	3.24*	−9.35	16.15***	+8.36
ME7	Intraperitoneal	2.51ns	−10.00	10.65**	+13.32
ME7	Oral	7.23**	−11.44	3.43ns	+4.65

Following ANOVA of incubation period data, the statistical significance of the variance ratios produced were calculated using F tests. The levels of statistical significance are indicated: ^ns Not significant (p > 0.05);

*p < 0.05;

**p < 0.01;

***p < 0.001.

The variance ratios and percentage differences in mean incubation periods are displayed between Schwann cell PrP knock-out mice and combined control groups. For comparison, the percentage difference in mean incubation periods within the control groups was calculated as the difference between the largest outlying control group (floxed PrP) and the remaining control groups. The difference in incubation periods observed between Schwann cell PrP knock-out mice and controls, following peripheral routes of inoculation (intraperitoneal and oral), is comparable to that observed among groups of animals expressing PrP normally, with similar statistical significance.