Results

Contingency Tables

Task 6: To conduct a chi-squared test, drag the variable nationality to the box called Rows, nationality to Columns, and frequency to Counts.

Task 7: Compute and interpret the odds ratio for Task 6.

Contingency Tables
		hands
nationality		One Handed	Two Handed	Total
Dutch	Count	120.000	578.000	698.000
	Expected count	110.041	587.959	698.000
	% within row	17.192 %	82.808 %	100.000 %
	% within column	87.591 %	78.962 %	80.322 %
	% of total	13.809 %	66.513 %	80.322 %
	Pearson residuals	0.949	-0.411
English	Count	17.000	154.000	171.000
	Expected count	26.959	144.041	171.000
	% within row	9.942 %	90.058 %	100.000 %
	% within column	12.409 %	21.038 %	19.678 %
	% of total	1.956 %	17.722 %	19.678 %
	Pearson residuals	-1.918	0.830
Total	Count	137.000	732.000	869.000
	Expected count	137.000	732.000	869.000
	% within row	15.765 %	84.235 %	100.000 %
	% within column	100.000 %	100.000 %	100.000 %
	% of total	15.765 %	84.235 %	100.000 %

Chi-Squared Tests
	Value	df	p
Χ²	5.437	1	0.020
N	869

Odds Ratio
		95% Confidence Intervals
	Odds Ratio	Lower	Upper	p
Odds ratio	1.881	1.098	3.221
Fisher's exact test	1.880	1.085	3.437	0.019

Task 6: The value of the chi-square statistic is 5.44. This value has a two-tailed significance of p = .020, which is smaller than .05 (hence significant), which suggests that the pattern of bike riding (i.e., relative numbers of one- and two-handed riders) significantly differs in English and Dutch people. The significant result indicates that there is an association between whether someone is Dutch or English and whether they ride their bike one- or two-handed.

Looking at the Contingency Table, this significant finding seems to show that the ratio of one- to two-handed riders differs in Dutch and English people. In Dutch people 17.2% ride their bike one-handed compared to 82.8% who ride two-handed. In England, though, only 9.9% ride their bike one-handed (almost half as many as in the Netherlands), and 90.1% ride two-handed. If we look at the standardized residuals we can see that the only cell with a residual approaching significance (a value that lies outside of ±1.96) is the cell for English people riding one-handed (z = -1.9). The fact that this value is negative tells us that fewer people than expected fell into this cell.

Task 7:

The odds of someone riding one-handed if they are Dutch are:

$ $

The odds of someone riding one-handed if they are English are:

$ $

Therefore, the odds ratio is:

$ $

In other words, the odds of riding one-handed if you are Dutch are 1.9 times higher than if you are English (or, conversely, the odds of riding one-handed if you are English are about half that of a Dutch person).

Write it up!

There was a significant association between nationality (Dutch or English) and whether a person rides rode their bike one- or two-handed, $ $ (1) = 5.44, p < .05. This represents the fact that, based on the odds ratio, the odds of riding a bike one-handed were 1.9 time higher for Dutch people than for English people. This supports Field’s argument that there are more one-handed bike riders in the Netherlands than in England and utterly refutes Mayer’s competing theory. These data are in no way made up.