Q3.1. A good experiment must include: groups that differ only in the hypothesized causal factor(s). at least one group that includes a potentially confounding factor. at least one group that differs from the control in multiple ways groups that allow for many comparisons, including those not directly related to the hypothesis. Q3.2. Why is replication important to consider when designing an experiment? Replication provides the baseline condition for the independent (treatment) variable Replication ensures your results apply only to specific cases O Replication introduces systematic variation into an experiment. Replication reduces the chances that a rare result leads you to the wrong conclusion. Use the following passage to answer the next 4 questions A farmer who grows blackberries has found his harvest to be lower than usual. He suspects that some animals are eating the berries before he can pick them. The farmer thinks it may be either birds (landing on the bushes to feast on berries) or rodents (climbing the bushes from below to munch on berries). He decides to first test the hypothesis that birds are eating his berries, and consults with a local expert on how best to prevent the birds from eating berries. He has eight fields with 10 rows of berry bushes in each field. In one of his fields (depicted below, as viewed from above), he covers half of the rows with nets that will prevent birds from landing on the bushes, and he leaves the other half uncovered. Over the course of 8 weeks, he counts the berries harvested from each row of bushes in the test field.