Eight schoolchildren, chosen at random from the first year of a large school, were given,without prior warning, a mathematical task, and the time taken (in minutes) by each child tocomplete the task was recorded.The following day the children were instructed how to perform such tasks efficiently, and aweek later they were tested again on a similar task. Once again, the time taken to complete thetask was recorded for each child and the results were as follows.Time taken (minutes)Child1 23 4 56 7 8Before instruction2620172123242118After instruction 19 1413 161918 16 17(a) Find a 90% confidence interval for the mean time taken by first year children (i) beforeinstruction, and (ii) after instruction, assuming that times are normally distributed.(b) Find a 90% confidence interval for the mean difference between times before and afterinstruction, for first year children.(c) Approximately how many children would have been needed in the sample in order toachieve a confidence interval in part (b) whose total width is 2 minutes?

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Answered: Eight schoolchildren, chosen at random…

Advanced Engineering Mathematics

10th Edition

ISBN:9780470458365

Author:Erwin Kreyszig

Publisher:Erwin Kreyszig

Chapter2: Second-order Linear Odes

Section: Chapter Questions

Problem 1RQ

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