A medical researcher wants to determine how long patients survive once diagnosed with AIDS. Using data collected on a randomly selected group of 40 patients with the disease, she observes an average survival time(time until death) of 60 months with a standard deviation of 10 months. Using a 99% level of confidence, estimate the population mean survival time f or those diagnosed with AIDS. Express the estimate in a sentence.
please, Any help means ALOT
please, Any help means ALOT
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It's a large sample (n >= 30), so you use the z-statistic.
n = 40, mean = 60, s = 10, a = .01
That means you use z = 2.575 by the standard z-table. The confidence interval is just plugging in the values:
(mean +/- 2.575(s/sqrt(n))) = (60 +/- 2.575(10/sqrt(40))) = (55.93, 64.07)
Thus, there is 99% confidence that the population mean is between 55.93 and 64.07.
n = 40, mean = 60, s = 10, a = .01
That means you use z = 2.575 by the standard z-table. The confidence interval is just plugging in the values:
(mean +/- 2.575(s/sqrt(n))) = (60 +/- 2.575(10/sqrt(40))) = (55.93, 64.07)
Thus, there is 99% confidence that the population mean is between 55.93 and 64.07.