RESEARCH METHOD COHEN ok

544 QUANTITATIVE DATA ANALYSIS
Box 24.37
Means and standard deviations for a t-test
Group statistics
How well learners are cared for,
guided and supported
Who are you N Mean SD SE mean
Leader/SMT member
Teachers
347
653
8.37
8.07
2.085
2.462
0.112
0.096
Box 24.38
The Levene test for equality of variances in a t-test
Independent samples test
Levene’s test
for equality
of variances
t-test for equality of means
How well
learners are
cared for,
guided and
supported
Equal variances
assumed
Equal variances
not assumed
95 % confidence
interval of the
difference
Sig. Mean SE
F Sig. t df (2-tailed) difference difference Lower Upper
8.344 0.004 1.92 998 0.055 0.30 0.155 0.006 0.603
2.02 811.922 0.044 0.30 0.148 0.009 0.589
Having discovered which row to follow, in our
example it is the second row, we go along to the
column ‘Sig. (2-tailed)’. This tells us that there is a
statistically significant difference between the two
groups – leaders/SMT and the teachers – because
the significance level is 0.044 (i.e. ρ0.05). Hence it
is sometimes important to know whether equal
variances are to be assumed or not to be assumed.
In the example here we find that there is
astatisticallysignificantdifferencebetweenthe
means of the two groups, i.e. the leaders/SMT
do not share the same perception as the teachers
that the learners are well cared for, guided and
supported, typically the leaders/SMT are more
generous than the teachers. This is of research
interest, e.g. to discover the reasons for, and impact
of, the differences of perception. It could be, for
example, that the leaders/SMT have a much rosier