document.write( "Question 617081: A study was conducted to estimate the mean amount spent on birthday gifts for a typical family having two children. A sample of 180 was taken, and the mean amount spent was $219.76. Assuming a standard deviation equal to $41.77, find the 99% confidence interval for µ, the mean for all such families. \n" ); document.write( "
Algebra.Com's Answer #388125 by ewatrrr(24785)\"\" \"About 
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document.write( "Hi, 
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document.write( "A study was conducted to estimate the mean amount spent on birthday gifts for a typical family having two children. 
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document.write( "A sample of 180 was taken, and the mean  $219.76. Assuming SD = $41.77, 
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document.write( "find the 99%\"z+=+2.576\" confidence interval for µ, the mean for all such families. 
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document.write( "ME = 2.576[41.77/sqrt(180)] 		
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document.write( "CI: 219.76-ME < u < 219.76 + ME	
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