In a survey, 17 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $43.3 and standard deviation of $13.9. Construct a confidence interval at a 80% confidence level. Express your answer in the format of ¯xx¯ ±± Error. $ ±± $
In a survey, 17 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $43.3 and standard deviation of $13.9. Construct a confidence interval at a 80% confidence level.
Express your answer in the format of ¯xx¯ ±± Error.
$ ±± $
The mayor is interested in finding a 98% confidence interval for the mean number of pounds of trash per person per week that is generated in city. The study included 180 residents whose mean number of pounds of trash generated per person per week was 34.2 pounds and the standard deviation was 7.4 pounds.
a. To compute the confidence interval use a ? t z distribution.
b. With 98% confidence the population mean number of pounds per person per week is between and pounds.
c. If many groups of 180 randomly selected members are studied, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population mean number of pounds of trash generated per person per week and about percent will not contain the true population mean number of pounds of trash generated per person per week.
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