Question

Difference of proportions problem. Biofeedback is a treatment technique in which people are trained to improve their health by using signals from their own bodies. A study was conducted to compare a biofeedback treatment for chronic pain with an NSAID medical treatment. A group of 2100 newly diagnosed chronic pain patients were randomly assigned to receive one of the two treatments. After six weeks of treatments, the pain level of the patients was assessed and the results are shown in the table below: Significant Reduction in Pain TREATMENT Yes No Total BioFeedback 580 450 1,030| NSAID 670 400 1,070 Total 1,240 840 2,100 d. Based on the result of a Null Hypothesis test that there is no difference in the proportion of patients answering YES between Biofeedback treatment and NSAID treatment, we would fail to reject the Null Hypothesis for a two-tailed test with an alpha level of.01. True False

Answer 1

Answer)

N1 = 1030 , P1 = 580/1030

N2 = 1070, P2 = 670/1070

Test statistics z = (P1-P2)/standard error

Standard error = √{p*(1-p)}*√{(1/n1)+(1/n2)}

P = pooled proportion = [(p1*n1)+(p2*n2)]/[n1+n2]

After substitution

Test statistics z = -2.94

From z table, p(z>2.33) = p(z<-2.33) = 0.01

That is rejection region is

Reject Ho if test statistics is less than -2.33 or greater than 2.33

As -2.94 is less than -2.33

We reject the null hypothesis Ho

So given statement is false