Question 138296: Confidence interval for the population mean: Use of the t distribution
A toy manufacturer wants to see how long, on average, a new toy captures children's attention. He tests 20 children selected at random and finds that their mean attention span is 31 minutes with a standard deviation of 6 minutes. If we assume that attention spans are normally distributed, find a 90 confidence interval for the mean attention span of children playing with this new toy. Then complete the table below.
Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place.
(If necessary, consult a list of formulas.)
What is the lower limit of the confidence interval
What is the higher limit of the confience interval
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A toy manufacturer wants to see how long, on average, a new toy captures children's attention. He tests 20 children selected at random and finds that their mean attention span is 31 minutes with a standard deviation of 6 minutes. If we assume that attention spans are normally distributed, find a 90 confidence interval for the mean attention span of children playing with this new toy. Then complete the table below.
Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place.
(If necessary, consult a list of formulas.)
What is the lower limit of the confidence interval: 28.68
What is the higher limit of the confience interval: 33.32
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Numbers are the result of running a T-Interval program on a Ti calculator
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Cheers,
Stan H.
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