# Homework Chapter 7

Assignment:

Objective: Apply concepts Independent Means Design

1. A researcher is contemplating various ways to design their study examining the effects of irrigation on crop yield. The first possible design would be to take a sample of yields from plots with a standard irrigation system and compare them to a sample of yields from plots without irrigation in the same region. Another would be to sample irrigated and non-irrigation crop yields from various regions and compare them, ensuring the plots are matched on the variable of region. A final option would be to sample crop yields from the same plots first before and then after installation of a standard irrigation system and compare the yields prior to irrigation to those following irrigation. The research design that would require an independent means t-test is ______________.

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Objective: Apply techniques Conducting an Independent Means t-test

1. A researcher predicts crop yields from plots with a standard irrigation system will be greater than yields from plots without irrigation in the same region. The scores for the research samples are presented in the table below, in units (bushels per hectare). Conduct a hypothesis test of the researcherâ€™s prediction with significance level .05. The populations should be defined as ______________.
 Plot Non-irrigated Plot Irrigated 1 163 29 208 2 131 30 198 3 160 31 208 4 183 32 198 5 168 33 186 6 135 34 177 7 179 35 173 8 143 36 203 9 161 37 203 10 154 38 192 11 162 39 186 12 163 40 185 13 166 41 176 14 181 42 184 15 132 43 199 16 149 44 197 17 169 45 199 18 148 46 202 19 169 47 188 20 158 48 200 21 143 49 201 22 150 50 191 23 178 51 194 24 147 52 185 25 170 53 202 26 171 54 178 27 169 55 212 28 180 56 180

1. For the research scenario described in problem 2, the hypotheses should be defined as ______________.
2. For the research scenario described in problem 2, the characteristics of the comparison distribution should be defined as ______________.
3. For the research scenario described in problem 2, the cutoff t score should be ______________.
4. For the research scenario described in problem 2, the calculated t-test result should be ______________.
5. For the research scenario described in problem 2, the hypothesis test decision should be ______________.
6. For the research scenario described in problem 2, the p-value associated with the t-test result is _____________.
7. For the research scenario described in problem 2, the conclusion as written in a published results section could be ______________.