Thirty pea seeds were randomly assigned to three groups of ten each. One group was germinated in the presence of chemical A, a second group with chemical B, and the third group served as a control. After five days, the length (in millimeters) of the primary root was measured. We wish to know if either or both of these chemicals affect root growth, and if so, if one is more effective than the other. Chemical A Chemical B Control 115 120 82 103 125 97 98 122 105 121 100 90 130 90 102 107 128 98 106 121 105 Required: What is the probability that a. all four plants emerged from treated seeds? b. Three or fewer emerged from treated seeds? c. at least one emerged from untreated seeds?