Wider Shoes for Wider Feet?

Figures & data

Figure 1. Widths of kids' feet, for boys and girls. The horizontal lines mark the average width for each group.

Table 1: Summary Statistics for widths of boys' and girls' feet.

	Boys	Girls
mean	9.190	8.784
standard deviation	0.4518	0.4936
sample size	20	19

Figure 2. Widths of kids' feet, plotted against length, for boys and girls.

Table

	1 if i^th child is a boy
di =
	0 if i^th child is a girl

Table 2: Regression results for ANCOVA model.

Source	SS	df	MS	F‐stat	p‐value
Model	4.535	2	2.267	15.31	<0.0001
Error	5.333	36	0.148
Total	9.868	38
Parameter	estimate	std err	t‐stat	p‐value
Intercept	3.851	1.113	3.46	0.0014
Foot Length	0.221	0.0496	4.45	<0.0001
Boy	0.233	0.129	1.80	0.0806

Figure 3. Widths of kids' feet, plotted against length, for boys and girls, with least squares regression function estimates superimposed.