Question

STATE: Velvetleaf is a particularly annoying weed in corn fields. It produces lots of seeds, and the seeds wait in the soil for years until conditions are right. The velvetleaf seed beetle feeds on the seeds and might be a natural weed control. Provided are the total seeds, seeds infected by the beetle, and percent of seeds infected for 28 velvetleaf plants. Seeds 2450 2504 2114 1110 2137 8015 1623 1531 2008 1716 Infected 135 101 76 24 121 189 31 44 73 12 Percent 5.5 4.0 3.6 2.2 5.7 2.4 1.9 2.9 3.6 0.7 Seeds 721 863 1136 2819 1911 2101 1051 218 1711 164 Infected 27 40 41 79 82 85 42 0 64 7 Percent 3.7 4.6 3.6 2.8 4.3 4.0 4.0 0.0 3.7 4.3 Seeds 2228 363 5973 1050 1961 1809 130 880 Infected 156 31 240 91 137 92 5 23 Percent 7.0 8.5 4.0 8.7 7.0 5.1 3.8 2.6 To access the complete data set, click the link for your preferred software format: Excel Minitab JMP SPSS TI R Mac-TXT PC-TXT CSV CrunchIt! Do a complete analysis of the percent of seeds infected by the beetle. Include a 90% confidence interval for the mean percent infected in the population of all velvetlead plants. PLAN: Select the correct stemplot for the given data 0 0 7 1 6 6 6 7 7 8 9 2 2 4 6 8 9 3 4 5 1 5 7 6 0 0 0 0 3 3 6 7 0 0 8 5 7 0 0 5 6 7 1 0 0 6 6 6 9 2 0 0 2 4 6 8 9 3 7 7 8 4 3 3 6 5 5 7 6 7 0 8 5 7 0 0 7 1 9 2 2 4 6 8 9 3 6 6 6 7 7 8 4 0 0 0 0 3 3 6 5 1 5 7 6 7 0 0 8 5 7 0 1 2 0 7 9 3 2 4 6 8 9 4 6 6 6 7 7 8 5 1 5 5 7 7 6 0 0 0 0 3 3 6 7 0 0 8 5 7 SOLVE: Find the mean of the samples, ?¯ , and the standard distribution, ? . (Enter your answers rounded to four decimal places.) ?¯= % ?= % Find the degrees of freedom, df . (Enter your answer as a whole number.) df = Find the ?∗ value for a 90% confidence interval for ? . (Enter your answers rounded to three decimal places.) ?∗= Give a 90% confidence interval for the mean percent infected in the population of all velvetleaf plants. 10.25 to 15.56 2.21 to 7.77 3.43 to 4.73 0.002 to 4.98 CONCLUDE: Do you think that the beetle is very helpful in controlling the weed? There was not enough information to say if it is an effective treatment or not. The beetle infects very little of the seeds, so it is unlikely to be effective in controlling velvetleaf. The beetle infects a large percentage of the seeds, so it is likely to be effective in controlling velvetleaf. The beetle infects some of the seeds, so it is likely to have a moderate effect on controlling velvetleaf.

Answer 1

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