Question

8. A sheep farmer suspects that when their animals are given a feed with a higher nitrogen content they tend to produce a greater weight of wool. To test this claim the farmer gave a random selection of 18 of their sheep a low nitrogen content feed and gave another random selection of 13 of their sheep a high nitrogen content feed. In the low nitrogen group it was found that the sheep produced an average of 12.5 pounds of wool with a standard deviation of 2.4 pounds. In the high nitrogen group it was found that the sheep produced an average of 16.2 pounds of wool with a standard deviation 3.1 pounds. [2 marks] Use these results to calculate a 95% confidence interval for the true mean difference in wool weight produced between the two groups. (You may order your two groups however you wish, but make your choice clear.) If needed, you may assume that the weight of wool produced under both types of feed is normally distributed. (b) (1 mark] Using your confidence interval from part (a), is it reasonable to say that the weight of wool produced between the low nitrogen group and the high nitrogen group is the same? Explain.

Answer 1

Date Page No 's dop -2 1542 (s. 212 [nd 23.267 Lz0.05 to 22.067 X z 125 S. Sazz. ht 13 h 2 S ez s² + S² h he 2.42 + 3.1 18 13 21.029 V C.I - (x, t - texbe, x - x + texse] = (10.5-162-(21067xl:090), 105-K27(30696R023 -(-588,-1.572)

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