Question

The mean cost to repair the smoke and fire damage that results from home fires of all causes is $11,389 (HomeAdvisor website, December 2014). How does the damage that results from home fires caused by careless use of tobacco compare? The DATAfile named TobaccoFires provides the cost to repair smoke and fire damage associated with a sample of 55 fires caused by careless use of tobacco products. Using past years' data, the population standard deviation can be assumed known with ? = $3,027.

Smoke and Fire Cost
17748
18429
17312
17622
23149
18340
23669
23006
18378
14160
21653
18060
20043
13859
22401
14970
15111
22320
21159
15628
19082
13832
20124
17819
16860
19042
16812
14610
16496
21287
17721
20229
23942
18937
21697
15098
18611
22137
19223
20527
16830
19854
20499
22607
13561
22031
22128
23200
23221
15096
15978
20768
22036
17678
23910

What is the 95% confidence interval estimate of the mean cost to repair smoke and fire damage that results from home fires caused by careless use of tobacco? Round your answers to whole dollar amounts. *NOTE* $10589 and $12189 are considered wrong according to the homework.

Answer 1

The statistical software output for this problem is:

One sample Z confidence interval:
? : Mean of variable
Standard deviation = 3027

95% confidence interval results:

Variable	n	Sample Mean	Std. Err.	L. Limit	U. Limit
Smoke and Fire Cost	55	19100	408.1606	18300.02	19899.98

Hence,

95% confidence interval will be:

($18300, $19900)