In the same scenario as 7.09, suppose you obtained a mean of $167 spent on transportation and a standard deviation of $40. Calculate a 95% confidence interval for the mean and select the values that come closest to those that would fill the spaces in the following interpretation: we can be 95% confident that they mean amount of money spent on transportation lies between _____ and _____ .'
Mathematics · College · Thu Feb 04 2021
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Given, a mean of $167 spent on transportation and a standard deviation of $40 .
First , calculate 95% confidence interval for mean
Assuming a normal distribution , critical value for 95% is 1.96
Margin of error = 1.96 ( standard deviation) = 78.40
Now calculate confidence interval
= ( Mean- margin of error , mean + margin of error)
= ( 167- 78.4 , 167+78.4 )
= ( 88.6 , 245.4 )
= Mean amount of money spent on transportation lies between 88.6 and 245.4 ..