Our bodies have a natural electrical field that is known to

Our bodies have a natural electrical field that is known to help wounds heal Does changing the field strength slow healing? A series of experiments with newts investigated this question. The data below are the healing rates of cuts (micrometers per hour) In a matched pairs experiment. The pairs are the two hind limbs of the same newt, with the body\'s natural electric field in one limb (control) and half the natural electric value in the other limb (experimental). We\'re Interested In knowing whether canceling the body\'s electric field reduces the healing rate. Give a 90% confidence interval for the difference in healing rates (control minus experimental)

Solution

A matched pair test is being conducted.

First set hypotheses as:

H0: mu1 = mu2

Ha: mu1 > mu2

Right tailed test at 10% significance level

mu1 = average of the full electric field

mu2 = average of half electric field

n = 14

df = 14-1 =13

t test can be conducted.

First calculate the mean std deviation for the two groups

Group  Group One    Group Two

  Mean 38.07 32.36

SD 11.54 9.34

SEM 3.08 2.50

N 14 14

t = 2.0239
  df = 13
  standard error of difference = 2.823

mu1-mu2 = 5.71

Critical value of t at 90% for df 13 =1.7613

Margin of error = 1.7613 (std error) = 4.9721

Confidence interval = (5.71, 10.6821)

The P-Value is .03125.

The result is significant at p < .10.

Hence we conclude that changing electric field lowers healing level.