Question 1069120: Bob Nale is the owner of Nale's Texaco GasTown. Bob would like to estimate the mean number of litres (L) of gasoline sold to his customers. Assume the number of litres sold follows the normal distribution with a standard deviation of 40 L. From his records, he selects a random sample of 29 sales and finds the mean number of litres sold is 89.
A) What is the point estimate of the population mean?
B) Develop a 98% confidence interval for the population mean.
C) Interpret the meaning of part (b).
If 100 such intervals were determined, the population (mean/variance)
would be included in about ____ intervals.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! The point estimate of the population mean is the sample mean, or 89 liters
98% CI using t df=28 0.99=2.467 We use the 0.01/0.02 table.
half interval is 2.467 +/-40/sqrt (29)=18.32 liters
interval is (70.68, 107.32)
We are 98% confident that the true value lies within this interval. We don't know the true value and never will, but we can be very confident it is contained here.
The population MEAN would be contained in about 98 intervals. We just wouldn't know which 98.
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