1. Sixteen batches of the plastic were made, and from each batch one test item was molded. Each test item was randomly a

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1 Sixteen Batches Of The Plastic Were Made And From Each Batch One Test Item Was Molded Each Test Item Was Randomly A 1 (79.79 KiB) Viewed 80 times

1 Sixteen Batches Of The Plastic Were Made And From Each Batch One Test Item Was Molded Each Test Item Was Randomly A 2 (74.4 KiB) Viewed 80 times

1. Sixteen batches of the plastic were made, and from each batch one test item was molded. Each test item was randomly assigned to one of the four predetermined time levels, and the hardness was measured after the assigned elapsed time. The results are shown below; X is the elapsed time in hours and Y is hardness in Brinell units. Assume that first-order regression model is appropriate. Please do all the parts by hand. (40 pts.; 4 each) 196 hardness time 199 116 205 16 16 200 116 (218 (24 220 24 215 24 223 24 (237 32 234 32 (235 32 230 32 250 140 248 140 253 140 (246 140
a a e. Obtain a 98 percent confidence interval for the mean hardness of molded items with an elapsed time of 30 hours. Interpret your confidence interval. f. Obtain a 98 percent prediction interval for the hardness of a newly molded test item with an elapsed time of 30 hours. g. Obtain a 98 percent prediction interval for the mean hardness of 10 newly molded test items, each with an elapsed time of 30 hours. h. Set up the ANOVA table. i. Test by means of an F test whether or not there is a linear association between the hardness of the plastic and the elapsed time. Use State the alternatives, decision rule, and conclusion. j. Calculate and comment.