Question

19. Identify the following:
    1. x
    2. n
    3. p’
    4. sqrt(p’*(1-p’)/n)
20. Define the random variables X and P’ in words.
21. Construct a 95% confidence interval for the proportion of all customers who experienced an interruption in high-speed service during the previous month.
22. You wish to conduct your own study to determine the proportion of customers who experienced an interruption in high-speed service during the previous month. What sample size would be needed for the estimate to be within 2 percentage points with 99% confidence?

For 29 through 34, follow one of the procedures we have previously used to test each hypothesis:

29. Suppose that the mean time spent on Facebook is 19.5 minutes with a standard deviation of 12 minutes. A study of 100 visits shows a sample mean of 21.5 minutes. Use a = 0.05 to test whether the mean time spent on Facebook has increased.

I AM DOING IT USING EXCEL, SO PLEASE EXPLAIN IT TO ME USING EXCEL AS WELL. PLEASE BE CLEAR

Answer 1

a. T-no. of events b, n = no. of trials C, p = sample proportion = d, sqrt(p * (1-ข้า/n)-estimate of standard error of 20.025 1.959963985 Use ercel commend: "- NORM.INV1 0.025,0,1)" 95% C.1. for proportion; p(1-p) , p+ Zo.025 P0.025 7l 7l Zo.005 2.5758 Use excel commend " = ROỤŅD(NORM.INV (1-0.005.0. Î).4)" Margin of error 0.01 or, Zo.005 pa-, p-= 0.01 7l or, n-72.005 * p * (1-p)/(0.01)2 (rounded into whole number)

Let μ = population mean 19.5 Alternative hypothesis, H1:u> 19.5 Null hypothesis, Ho: σ-population sd- 12 n 100 X = 21.5 Excel Formula z Vn(x -1.6667Use" round(SQRT(D8) (D9-19.5)/12,4)" Z0.051.6449 Use"-ROUND(NORM.INV(1-0.05,0,1),4)" Test Statistic Critical value- p-value P(Z> 1.6667IZN(O,1)0.0478 Use"-ROUND(1-NORM.DIST(1.667,0,1,TRUE),4) Since Z-value-critical value or p-value<0.05 so we reject Null hypothesis Thus the mean time spent on Facebook has increased