A crop scientist is conducting research with a drought resistant corn hybrid. She is interested in determining if increasing the spacing between these plants will increase yield. She prepares 30 single acre plots and randomly assigns 15 to have normal spacing while the other 15 are planted with an expanded spacing. The resulting average yield for each group of 15 plots was recorded. Select all that apply.

Select one or more:
a. The explanatory variable is whether the corn plants had normal spacing or expanded spacing.
b. The response variable is the yield of the crops.
c. The explanatory variable is the yield of the crops.
d. The response variable is whether the corn plants had normal spacing or expanded spacing.
e. This study is best described as an experiment.
f. This is best described as an observational study.

Acell phone company offers two plans to its subscribers. at the time new subscribers sign up, they are asked to provide some demographic information. the mean yearly income for a sample of 40 subscribers to plan a is $45,000 with a standard deviation of $9,200. for a sample of 25 subscribers to plan b, the mean income is $64,300 with a standard deviation of $7,100. at the 0.025 significance level, is it reasonable to conclude the mean income of those selecting plan b is larger? assume unequal population standard deviations. hint: for the calculations, assume the plan a as the first sample. what is the decision rule? (negative amount should be indicated by a minus sign. round your answer to 3 decimal places.) compute the value of the test statistic. (negative amount should be indicated by a minus sign. round your answer to 2 decimal places.) what is your decision regarding h0 ? reject h0 fail to reject h0 compute the p-value. less than 0.01 between 0.01 and 0.025 between 0.025 and 0.05 between 0.05 and 0.10 greater than 0.10