To improve quality, productivity, and timeliness, many American industries employ self-managed work teams (SMWTs). Because SMWTs require that employees be trained in interpersonal skills, they can have potential positive spillover effects on a worker’s family life. The link between SMWT work characteristics and workers’ perceptions of positive spillover into family life was investigated in the Quality Management Journal (Summer 1995). Survey data were collected from 114 AT&T employees who work in SMWTs at an AT&T technical division. The workers were divided into two groups: (1) those who reported positive spillover of work skills to family life and (2) those who did not report positive work spillover. The two groups were compared on a variety of job and demographic characteristics, one of which was the use of creative ideas (measured on a 7-point scale, where the larger the number, the more of the characteristic indicated). The data (simulated from summary information provided in the Quality Management Journal article) are saved in the file.

a. One comparison of interest to the researchers is whether the mean creative use of ideas scale score for employees who report positive spillover of work skills to family life differs from the mean scale score for employees who did not report positive work spillover. Give the null and alternative hypotheses that will allow the researchers to make the comparison.

b. Discuss whether it is appropriate to apply the largesample z-test to test the hypotheses, part a.

c. The results of the test are shown in the XLSTAT printout below. Interpret these results. Make the appropriate conclusion using α = .05.

XLSTAT output for Exercise 8.118

d. A 95% confidence interval for the difference between the mean use of creative ideas scale scores is also shown on the XLSTAT printout. Interpret this interval. Does the inference derived from the confidence interval agree with that from the hypothesis test?

e. The data also include the qualitative variable, Gender, for each worker. The researchers want to know whether the proportion of male workers in the two groups are significantly different. A Minitab printout of the analysis is also shown at the bottom of p. 494. Fully interpret the results in the words of the problem.

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Summary statistics (Data / Subsamples): Variable CREATIVE | NOSPILL CREATIVE SPILLOV Observations Minimum Maximum Mean 67 3.0000 5.0000 4.4478 47 5.0000 6.0000 5.2553 z-test for two independent samples / Two-tailed test: 95% confidence interval on the difference between the means: [-0.9865, -0.6287] Difference z (Observed value) Iz] (Critical value) p-value (Two-tailed) alpha -0.8076 -8.8470 1.9600 <0.0001 0.05 Std. deviation 0.5304 0.4408