# Confidence Interval Using Paired Sample T Test

A company has 1.100 inventory items. In a sample of 120 items, the historical cost of each item was compared with the audited value, and 10 items differed in their historical costs and audited values. These values are shown below. Construct a 99% confidence interval estimate of total population difference in the historical cost and audited value

Sample Number Historical Cost ($) Audited Value ($)

9 142 183

17 88 90

28 239 285

35 344 226

43 193 268

51 252 210

73 27 128

95 172 177

107 163 144

119 87 116

$( ) < Total difference < $( )

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This solution is comprised of a detailed explanation of confidence interval using paired t test. This solution mainly discusses the calculation of 99% confidence interval using paired t test and the calculation of confidence interval with formula and calculations was done in excel for better clarity and understanding of confidence interval using paired t test.