SOLUTION: In a survey, 25 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 $11

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Question 1165341: In a survey, 25 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 $11.6. Estimate how much a typical parent would spend on their child's birthday gift (use a 95% confidence
level). Give your answers to 3 decimal places.
Express your answer in the format of
¯x ± Error.
$__________ ± $_____________

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
this is a t-distribution. The half-interval is t df=24, 0.975 *s /sqrt(n)
=2.064 * 11.6/sqrt(25)
=$4.788
add to interval subtract from interval ($38.512, $48.088)
and the format requested $43.30 +/- $4.788