Methods of Communication Research and Statistics

In this exercise, you use the survey of the MCRS students from 2006. This database: MCO_1.2006.sav

Use a t-test to see whether men spend more hours watching television at weekends than women. Use the variables 'v6hour' and 'v1' to do so.

Use a t-test to see whether men spend more hours watching television at weekends than women.

We want to compare two groups or sample groups (men and women) in respect of one quantitative variable, namely the number of hours they spend watching television at weekends (v6hour). We therefore have to carry out a t-test for independent scores (INDEPENDENT SAMPLES t-TEST).

First describe the variables and correct any problems in the variables (value labels for men). The sample group is so large (N > 100) that we do not have to check the shape of the distribution; with an abnormal distribution in the population too, we can carry out the t-test.

Group Statistics

v1 N Mean Std. Deviation Std. Error Mean

v6hour 0 men 773 2,7762 1,83033 ,06583

1 women 781 2,7759 1,98384 ,07099

Independent Samples Test

Levene's Test for Equality of Variances t-test for Equality of Means

95% Confidence Interval of the Difference

F Sig. t df Sig. (2-tailed) Mean Difference Std. Error Difference Lower Upper

v6hour Equal variances assumed ,198 ,656 ,003 1552 ,998 ,00027 ,09685 -,18971 ,19025

Equal variances not assumed ,003 1544,412 ,998 ,00027 ,09681 -,18963 ,19017

The results we find are as follows. The variances in the two random samples are not significantly different (SD_women = 1.83, SD_men = 1.98), F = 0.20; p = 0.656, so we use the result after 'equal variances assumed'. There appears to be no significant difference in the average number of hours spent watching television every day in the weekend between men (M = 2.78; SD = 1.98) and women (M = 2.78; SD = 1.83), t (1552) = 0.003; p = 0.499 unilateral; 95% CI [-0.19, 0.19].

Syntax
*Description of the variables.
FREQUENCIES
  VARIABLES=v1
  /ORDER= ANALYSIS
*Define Variable Properties.
*v1.
VALUE LABELS v1
     0 'women'
     1 'men'
EXECUTE.
*Description of v6hour with EXPLORE.
EXAMINE
  VARIABLES=v6hour
  /PLOT BOXPLOT
  /COMPARE GROUP
  /STATISTICS DESCRIPTIVES EXTREME
  /CINTERVAL 95
  /MISSING LISTWISE
  /NOTOTAL.

*T-test without correction for extremes and skewness.
T-TEST
  GROUPS = v1(0 1)
  /MISSING = ANALYSIS
  /VARIABLES = v6hour
  /CRITERIA = CI(.95) .

SPSS exercise 3.1