SOLUTION: A researcher is interested in finding a 90% confidence interval for the mean number minutes students are concentrating on their professor during a one hour statistics lecture. The

Question 1197535: A researcher is interested in finding a 90% confidence interval for the mean number minutes students are concentrating on their professor during a one hour statistics lecture. The study included 107 students who averaged 32.4 minutes concentrating on their professor during the hour lecture. The standard deviation was 13.7 minutes. Round answers to 3 decimal places where possible.
a. To compute the confidence interval use a
?
distribution.
b. With 90% confidence the population mean minutes of concentration is between
and
minutes.
c. If many groups of 107 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 minutes of concentration and about
percent will not contain the true population mean minutes of concentration.
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!


Hi  

'Standard Distribution': µ = 32.4 and σ =13.7
n 107
 
 90% confidence interval:  z = 1.645  |  Invnorm(.9 + .1/2) = Invnorm(.95) 
   = 2.179
32.5 - 2.179  < 32.5+ 2.179
30.321  < 34.679

90% confident,  interval will contain true population mean

Wish You the Best in your Studies.

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