In an experiment to determine whether there is a systematic difference between the weights obtained with two different mass balances, six specimens were weighed, in grams, on each balance. The following data were obtained: Specimen A B 1 13.76 13.74 2 12.47 12.45 3 10.09 10.08 4. 8.91 8.92 5 13.57 13.54 6 12.74 12.75 Can you conclude that the mean weight differs between the two balances? i). State the null and alternative hypotheses. ii). Compute the test statistic. iii). State a conclusion using the a =0.05 level of significance.
An educational researcher devised a wooden toy assembly project to test learning in 6-year-olds. The time in seconds to assemble the project was noted, and the toy was disassembled out of the child's sight. Then the child was given the task to repeat. The researcher would conclude that learning oCcurred if the mean of the second assembly times was less than the mean of the first assembly times. Find the 99% confidence interval for the difference in means. Child 1 5 6 7 3 4 2 Trial 108 140 154 115 130 111 108 Trial 2 99 118 154 96 107 102 110
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