Homework1_S10_solution

Homework1_S10_solution - Solution to Assignment 1...

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Solution to Assignment 1 Convenience Assignment It is easiest to plant one variety on 18 plots on one side of the field and the other variety on the 18 plots on the other side. Below is a picture of such and assignment and the yields, in bushels per acre, for each plot. The yields and a summary of those yields are given below. A 130 A 149 A 139 B 155 B 137 B 145 A 149 A 133 A 152 B 131 B 147 B 136 A 141 A 156 A 137 B 146 B 132 B 148 A 150 A 142 A 155 B 136 B 152 B 133 A 139 A 155 A 139 B 147 B 137 B 153 A 155 A 138 A 150 B 137 B 145 B 136 Variety n mean std. dev A 18 144.9 8.29 B 18 141.8 7.65 () 659 . 2 18 1 18 1 976 . 7 1 1 difference of error std. 976 . 7 6233 . 63 34 65 . 7 17 29 . 8 17 2 1 1 2 2 2 2 = + = + = = = + = + + = B A p B A B B A A p n n s n n s n s n s Using a two-sample t-test, the value of the test statistic is ( ) 17 . 1 659 . 2 8 . 141 9 . 144 = = t with a two-sided P-value of 0.25. This indicates that although variety A has a slightly higher mean yield than variety B, the two varieties are not statistically different. This is probably not a fair comparison. One side of the field may be more fertile than the other or get more water than the other. There could be many
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This note was uploaded on 01/30/2011 for the course STAT 402 taught by Professor Staff during the Fall '08 term at Iowa State.

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Homework1_S10_solution - Solution to Assignment 1...

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