A Company Runs a Three-Day Workshop on Strategies for Working

Multiple Choice

A company runs a three-day workshop on strategies for working effectively in teams. On each day, a different strategy is presented. Forty-eight employees of the company attend the workshop. At the outset, all 48 are divided into 12 teams of four. The teams remain the same for the entire workshop. Strategies are presented in the morning. In the afternoon, the teams are presented with a series of small tasks. The number of these tasks completed successfully, using the strategy taught that morning, is recorded for each team. The mean number of tasks completed successfully by all teams each day and the standard deviation are computed. The results follow. The researchers did an ANOVA F test of the data and obtained the following results. In this example, we notice that:

A) there is clear evidence of bias in the results. This is undoubtedly due to the lack of blinding on the part of the subjects.
B) the data show very strong evidence of a violation of the assumption that the three populations have the same standard deviation.
C) ANOVA cannot be used on these data, because the sample sizes are less than 20.
D) the assumption that the data are independent for the three days is unreasonable, because the same teams were observed each day.