Question

Biologists studying the healing of skin wounds measured the rate at which new cells closed a cut made in the skin of an anesthetized newt. Here are data from a random sample of 18 newts, measured in micrometers (millionths of a meter) per hour: 29, 27, 34, 40, 22, 28, 14, 35, 26, 35, 12, 30, 23, 18, 11, 22, 23, 33.

90% confidence level (22.254,29.080)

(A) Consider a test of H0 : μ = 25 vs. HA : μ does not equal 25 using significance level 0.10 (not the usual 0.05). Based on the 90% interval and no new calculations, say whether you would reject H0.

(B) Test whether these data are strong evidence that the population mean rate is significantly greater than 25 at level α = .05. (Note that you have a 90% confidence interval, not a 95% interval, and the interval was two-sided, but this test is one-sided, so the interval isn’t directly useful for deciding this test.)

(C) Suppose the problem statement included the addition, “Prior experience in the lab indicates that the population standard deviation is close to σ = 8 (micrometers per hour).” This would call for which changes to your confidence interval calculation? Write down the letters of all that are correct.

i. Replace x ̄ withx ̄ /n.

ii. Replace t_17,.05 with z_.05 = 1.645.

iii. Replace sqrt(n) with n.

iv. Replace s (calculated from the data) with σ = 8.

v. Replace s (calculated from the data) with σ /√n = 8/√18 .

Answer 1

Dear student,
I am waiting for your feedback. I have given my 100% to solve your queries. If you are satisfied by my given answer. Can you please like it☺