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The manufacturer of a new line of ink-jet printers would like to include as part

ID: 3207331 • Letter: T

Question

The manufacturer of a new line of ink-jet printers would like to include as part of its advertising 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 t Distribution Table.)

3690, 2560, 2550, 2500, 3170, 2610, 2990, 3870, 3170, 2510

a. What is the point of the estimate of the population mean? (Round your answer to the nearest whole number.)

b. Develop a 99% confidence interval for the population mean. (Round your answer to 2 decimal places)

The manufacturer of a new line of ink-jet printers would like to include as part of its advertising 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 t Distribution Table.)

3690, 2560, 2550, 2500, 3170, 2610, 2990, 3870, 3170, 2510

a. What is the point of the estimate of the population mean? (Round your answer to the nearest whole number.)

b. Develop a 99% confidence interval for the population mean. (Round your answer to 2 decimal places)

Explanation / Answer

x

3690

2560

2550

2500

3170

2610

2990

3870

3170

2510

( a )

Sample mean (x bar) = S x / n = 29620/10 = 2962

Answer: The point estimate of the population mean is 2962.

( b )

Confidence Interval:

x bar (-/+) E

x bar = 2962

E = tc * ( s / Ön)

tc is the critical value for 9 degrees of freedom at 1% level of significance. We get this value using the t-table as 3.250.

s is the sample standard deviation

s = Ö [S(x – x bar)^2 / (n-1) = Ö2314760/9 = 507.1445

E = 3.250 * (507.1445/Ö10) = 521.2128

x bar (-/+) E

2962 (-/+) 521.2128

2440.79 and 3483.21

Answer: The 99% confidence interval is (2440.79 to 3483.21)

x

3690

2560

2550

2500

3170

2610

2990

3870

3170

2510