Question

Seved Check my work mode: This shows what is correct or incorrect for the work you have completed so far. It does 7 PrintTech, Inc is introducing a new line of ink-jet printers and would like to promote the number of pages a user can expect from a print cartridge. A sample of 10 cartridges revealed the following number of pages printed. (Use tDistribution Table) 12.5 3,072 3,025 2,472 2,552 points 2,579 3,187 2,920 2,575 3,034 3,664 picture Click here for the Excel Data File a. What is the point estimate of the population mean? (Round your answer to 2 decimel places) Answer is complete but not entirely correct. Estimated pepultion mean 2897 90 b. Develop a 90% confidence interval for the population mean (Round your answers to 2 decimal places) Answer is complete but not entirely correct. Contidence intenval for the population mean is behween 2676 20 nd 3.119.60 7 of 8 Next <Prev Grire

Answer 1

a) Point estimate of population mean x bar = 2907.9

b) 90 % confidence interval:

From the given sample data we get - Sample mean x bar = 2907.9. sample standard deviation s = 371.4262, n = 10 and C=0.90 We have asked to find 90 % confidence interval. Here population standard deviation is not known hence we use T interval. 90% confidence interval: x bar - E< <x bar + E Where E = 0.90 * (s / vn) = 1.83 * (371.4262/10) = 215.31 so x bar - E = 2907.9-215.31 = 2692.59 x bar + E = 2907.9 +215.31 = 3123.21 Hence the required confidence interval is 2692.59 < | <3123.21 Rounded to 2 decimal places.

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