Question

In a study of the effectiveness of a fabric device that acts like a support stocking for a weak or damaged heart, 110 people who consented to treatment were assigned at random to either a standard treatment consisting of drugs or the experimental treatment that consisted of drugs plus surgery to install the stocking. After two years, 45% of the 60 patients receiving the stocking had improved and 36% of the patients receiving the standard treatment had improved. (Use a statistical computer package to calculate the P-value. Use pexperimental − pstandard. Round your test statistic to two decimal places and your P-value to four decimal places.)

z =

P =

Answer 1

As we are testing here the effectiveness of a fabric device that acts like a support stocking for a weak or damaged heart, therefore the null and the alternative hypothesis here are given as:

Now the sample proportions here are given as:
p1 = 0.45, p2 = 0.36

The pooled proportion is first computed as:

The standard error now is computed here as:

Now the test statistic here is computed as:

Therefore 0.96 is the test statistic value here.

The p-value here is computed from the standard normal tables as:

p = P(Z > 0.96) = 0.1695

Therefore 0.1695 is the required p-value here.