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MEASURES OF DIFFERENCE BETWEEN GROUPS AND MEANS 557 Box 24.61 Frequencies for variable one in the Friedman test The course encouraged and stimulated your motivation and willingness to learn Valid Not at all Very little A little Quite a lot A very great deal Total Total Frequency 1 13 64 79 32 189 191 Valid percent 0.5 6.9 33.9 41.8 16.9 100.0 Chapter 24 Box 24.62 Frequencies for variable two in the Friedman test The course encouraged you to take responsibility for your own learning Valid Not at all Very little A little Quite a lot A very great deal Total Total Frequency 1 9 64 85 30 189 191 Valid percent 0.5 4.8 33.9 45.0 15.9 100.0 (See http://www.routledge.com/textbooks/ 9780415368780 – Chapter 24, file Manual 24.12.) For more than two related samples (e.g. the same group voting for three or more items, or the same grouping voting at three points in time) the Friedman test is applied. For example, in Boxes 24.61 to 24.63 are three variables (‘The course encouraged and stimulated your motivation and willingness to learn’, ‘The course encouraged you to take responsibility for your own learning’ and ‘The teaching and learning tasks and activities consolidate learning through application’), all of which are voted on by the same group. The frequencies are given. Is there a statistically significant difference between the groups in their voting The Friedman test reports the mean rank and then the significance level; in the examples here the SPSS output has been reproduced (Boxes 24.64 and 24.65). Here one can see that, with a significance level of 0.838 (greater than 0.05), the voting by the same group on the three variables is not statistically significantly different, i.e. the null hypothesis is supported. The reporting of the results of the Friedman test can follow that of the Kruskal-Wallis test. For both the Kruskal-Wallis and the Friedman tests, as with the Mann-Whitney and Wilcoxon tests, not finding a statistically significant difference between groups can be just as important as finding a statistically significant difference between them, as the former suggests that nominal characteristics of the sample make no statistically significant difference to the voting, i.e. the voting is consistent, regardless of particular features of the sample. The k-sample slippage test from Conover (1971), as an alternative to the Kruskal- Wallis test, is set out in the accompanying web site: see http://www.routledge.com/textbooks/ 9780415368780 – Chapter 24, file 24.6.doc. Several data sets for use with SPSS are included on the accompanying web site, using fictitious data, thus: an SPSS data file on managing change: http://www.routledge.com/textbooks/ 9780415368780/, file ‘data file on change’

558 QUANTITATIVE DATA ANALYSIS Box 24.63 Frequencies for variable three in the Friedman test The teaching and learning tasks and activities consolidate learning through application Valid Very little A little Quite a lot A very great deal Total Frequency 6 71 92 22 191 Valid percent 3.1 37.2 48.2 11.5 100.0 Box 24.64 Rankings for the Friedman test Ranks The course encouraged and stimulated your motivation and willingness to learn The course encouraged you to take responsibility for your own learning The teaching and learning tasks and activities consolidate learning through application Box 24.65 Significance level in the Friedman test Mean rank 1.98 2.03 1.99 an SPSS data file on organizational culture: http://www.routledge.com/textbooks/ 9780415368780/ file ‘organizational culture data file’ an SPSS data file on mathematics scores and related variables: http://www.routledge. com/textbooks/9780415368780/ file ‘test results for mathematics’; the questionnaire that accompanies this file (in Word) is available at http://www.routledge.com/textbooks/ 9780415368780/, file ‘SPSS questionnaire on mathematics’ a Word file indicating all the SPSS files contained on the web site is available at: http://www.routledge.com/textbooks/ 9780415368780/, file ‘SPSS FILES ON THE WEB SITE’. Test statistics a N 187 Chi-square 0.353 df 2 Asymp. sig. 0.838 a. Friedman Test

558 QUANTITATIVE DATA ANALYSIS<br />

Box 24.63<br />

Frequencies for variable three in the Friedman test<br />

The teaching and learning tasks and activities consolidate learning through application<br />

Valid<br />

Very little A little Quite a lot A very great deal Total<br />

Frequency 6 71 92 22 191<br />

Valid percent 3.1 37.2 48.2 11.5 100.0<br />

Box 24.64<br />

Rankings for the Friedman test<br />

Ranks<br />

The course encouraged and<br />

stimulated your motivation and<br />

willingness to learn<br />

The course encouraged you to take<br />

responsibility for your own learning<br />

The teaching and learning tasks and<br />

activities consolidate learning<br />

through application<br />

Box 24.65<br />

Significance level in the Friedman test<br />

Mean rank<br />

1.98<br />

2.03<br />

1.99<br />

an SPSS data file on organizational<br />

culture: http://www.routledge.com/textbo<strong>ok</strong>s/<br />

9780415368780/ file ‘organizational culture<br />

data file’<br />

<br />

an SPSS data file on mathematics scores<br />

and related variables: http://www.routledge.<br />

com/textbo<strong>ok</strong>s/9780415368780/ file ‘test results<br />

for mathematics’; the questionnaire that<br />

accompanies this file (in Word) is available<br />

at http://www.routledge.com/textbo<strong>ok</strong>s/<br />

9780415368780/, file ‘SPSS questionnaire on<br />

mathematics’<br />

a Word file indicating all the SPSS<br />

files contained on the web site is available<br />

at: http://www.routledge.com/textbo<strong>ok</strong>s/<br />

9780415368780/, file ‘SPSS FILES ON THE<br />

WEB SITE’.<br />

Test statistics a<br />

N 187<br />

Chi-square 0.353<br />

df 2<br />

Asymp. sig. 0.838<br />

a. Friedman Test

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