Question

9. 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

1. Construct and interpret a 92% confidence interval for the average micrometers per hour for the healing rate for newts.

b) Is there convincing evidence that the average healing rate of newts will last longer than 36 micrometers per hour?

Answer 1

(a)

From the given data, the following statistics are calculated:

n = 18

= 25.6667

s = 8.3243

=0.8

df = 18 - 1 = 17

From Table, critical values of t = 1.862

Confidence Interval:

So,

Answer is:
(22.014, 29.320)

(b)

There is no convincing evidence that the average healing rate of newts will last longer than 36 micrometers per hour because all values in the confidence interval (22.014, 29.320) are less than 36.