An advertising company is interested in determining if there is a difference in the mean sales that will be generated for a soft drink company based on which shelf the soft drinks are located.There are four possible shelf levels.The ad company wants to control for store size.The following data reflect the sales for one week at each combination of shelf level and store size.
Based on the experimental design,the managers should conclude that they were justified in blocking on store size if they test using a 0.05 level of significance.

Question

An advertising company is interested in determining if there is a difference in the mean sales that will be generated for a soft drink company based on which shelf the soft drinks are located.There are four possible shelf levels.The ad company wants to control for store size.The following data reflect the sales for one week at each combination of shelf level and store size.
  Based on the experimental design,the managers should conclude that they were justified in blocking on store size if they test using a 0.05 level of significance.

Quizplus · Accepted Answer

Blocking is a technique used to control for the effects of extraneous variables or nuisance factors that could affect the outcome of an experiment. In this case, the store size could potentially affect the sales of the soft drinks, so the ad company decided to block on store size. By doing so, they ensure that each shelf level is equally represented across different store sizes, allowing them to make valid comparisons between shelf levels. Given that the data reflect the sales for one week at each combination of shelf level and store size, and assuming that the experiment is properly designed and executed, the managers should conclude that they were justified in blocking on store size when testing for differences in mean sales. A significance level of 0.05 is commonly used to determine whether the observed differences are statistically significant or simply due to chance.

An Advertising Company Is Interested in Determining If There Is