Question

In a survey, 32 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $45 and standard deviation of $10. Construct a confidence interval at a 90% confidence level. Give your answers to one decimal place.

Answer 1

Result:

In a survey, 32 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $45 and standard deviation of $10. Construct a confidence interval at a 90% confidence level. Give your answers to one decimal place.

n=32

Mean =45

SD=10

At 90% level, Table value t at 32-1 = 31 DF is 1.6955

=( 42.0, 48.0)

Confidence Interval Estimate for the Mean
Data
Sample Standard Deviation	10
Sample Mean	45
Sample Size	32
Confidence Level	90%
Intermediate Calculations
Standard Error of the Mean	1.7678
Degrees of Freedom	31
t Value	1.6955
Interval Half Width	2.9973
Confidence Interval
Interval Lower Limit	42.0027
Interval Upper Limit	47.9973