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. 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. Would a between subjects or a within subjects design be more efficient (require the smaller sample size)?

Sample site	Total Number Visits per Flower	Difference in Number of Visits per Flower Between Left Half & Right Half
1	1.49	0.06
2	1.00	0.00
3	1.89	1.04
4	0.70	0.20
5	1.00	0.00