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4.14 Thanksgiving spending
the 2009 holiday retail season, which kicked off on November 27,2009 (the day after Thanksgiving), had been marked by somewhat lower self-reported consumer spending that was seen during the comparable period in 2008. To get an estimate of consumer spending, 436 randomly sampled American adults were surveyed. Daily consumer spending for the six-day period after Thanksgiving, spanning the Black Friday weekend and Cyber Monday, averaged $84.71 with a standard deviation of 2.24.

The conditions of independence and normality need to be met before constructing a confidence interval.

a) What aspects of this scenario establish independence?

The 436 Americans in the survey were randomly sampled, and 436 is less than 10% of all Americans who shopped in the same period.
The data were collected by a survey, and the sample of 436 is greater than 30.
The sample data were collected from a six day period, and the population data was from a six day period.

b) What aspect of this scenario establishes normality?

The histogram is not normal and is unimodal.
The histogram is normal and is a discrete distribution
The histogram is fairly normal and only slightly skewed.
The histogram is not normal and is multimodal

c) Determine a 99% confidence interval for the data above.
( , )

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