# Written Assignment 1 Solutions.pdf - Assignment 1 Solutions...

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Assignment 1 Solutions
2.(5 marks)Letσ21be the population variance of CO amount (in mg) from filteredcigarettes.Letσ22be the population variance of CO amount (in mg) from unfiltered cigarettes.Hypotheses:H0:σ21=σ22,H0:σ216=σ22.Test statistic: The test statistic iss21/s22, which hasF20,7distribution.Observed value:Fobs= 9.428571/1.4107146.683544
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Using our tables, we find thatP(F20,76.16) = 0.01. From this we concludethatP(F20,7Fobs)<0.01.Since a single tail has probability less than 0.01, then two tails have probabilityless than2(0.01) = 0.02. Our p-value is less than0.02.We conclude that there is strong evidence againstH0.The data are consis-tent with the population standard deviations for CO amounts from filtered andnonfiltered cigarettes are different.Note:Some of you may have chosen to test atα= 0.2, in which case you wouldhave rejectedH0. Since we are not using this test to determine whether or notto use pooled procedures for a test on the mean, then we do not need to use anαlevel of0.2here.