Question 1145329
alpha(a) = 1 - (99/100) = 0.01
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critical probability(p*) = 1 - (a/2) = 0.995
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since the sample(21 days) < 30 and the population standard deviation is unknown, we find the critical value(CV) using the  t statistic
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degrees of freedom(DF) = 21 - 1 = 20
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Using p* and DF, the CV is 2.845
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standard error(SE) = sample standard deviation/square root(sample size) = 22.8/square root(21) = 4.975
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Margin of Error(ME) = CV * SE = 2.845 * 4.975 = 14.15 is approximately 14.2
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The 99% confidence interval for the mean number of daily calls received by the call Centre is 162.2 + or - 14.2 or (176.4, 148)
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