A training manager believes that a new interactive computer-based training package will help improve the production rate of order assemblers. She arranges for a production area of 21 experienced employees to complete the new training package over a 6 week period. Another group from the production area of 23 employees received no additional training. Following are the average production rates per person per hour based on a 12 week period following the training.
|Training Group||Control Group|
Recommendations: Before following these steps, screen your data for outliers and normality.
Two variables in dataset--productivity (dependent variable) and training variable (independent variable). Should like something like this:
Move dependent variable to top box (i.e., Test Variable(s)) and independent variable to lower box (i.e., Grouping Variable).
Indicate which two groups you want to include in the analysis. In my example I coded the training group as 1 and the control group as 2. Yours may be different. We only have two groups in this dataset.
Descriptive statistics by group.
Independent t-test results
Table 1 presents the means and standard deviations by group. The results show that the order assemblers in the training group produced about 10 more assemblies per person per hour (M = 53.48) than the assemblers in the control group (M = 43.52). Also, the employees in the training group had more homogeneous production rates (SD = 11.01) than the employees in the control group (SD = 17.15).
Since the measurements in the training group and control group were unrelated to each other, an independent t-test was performed. The assumption of homogeneous variances was satisfied (Levenes test, F = 2.36, p = .132). The mean score for the training group was significantly higher than the mean score for the control group, t = (.05, 42) = 2.27, p = .029. There was a large difference between the training and control groups (g=.71).
Mean Assemblies Per Person Per Hours and Standard Deviations
The new computer-based training package used with the training group had a significant and positive effect on production rates. Therefore, it is appropriate for management to consider providing the new training to employees in all the assembly areas.