Background info: An ecologist was planning a study to determine the effect of modifying flower color on pollinator visitation to Potentilla glandulosa. The following data represent the number of pollinator visits per flower (total number of visits per flower) and the difference between the left and right half of each plant in the number of pollinator visits per flower.

Question: Use these data to determine the sample size needed to detect a 30% reduction in pollinator visitation upon manipulation of flower color with ? =0.05 and ? = 0.2 **using parametric and non-parametric tests. Would a between subjects or a within subjects design be more efficient (require the smaller sample size)?

Summary of total pollinator visits/flower for whole plant and for each plant half. Sample Site Total Number Visits Difference in Number of Visits per per flower Flower between left half and right half 1.49 0.06 1.00 0.00 3 1.89 1.04 4 0.70 0.20 1.00 0.00