Carpal tunnel syndrome is a common wrist complaint resulting from a compressed n
ID: 3359501 • Letter: C
Question
Carpal tunnel syndrome is a common wrist complaint resulting from a compressed nerve, and it is often caused by repetitive wrist movements. In a randomized controlled trial, among 73 patients treated with surgery and evaluated one year later, 67 were found to have successful treatments. Among 83 patients treated with splints and evaluated one year later, 60 were found to have successful treatments (based on data from “Splinting vs Surgery in the Treatment of Carpal Tunnel Syndrome,” by Gerritsen, et al., Journal of the American Medical Association, Vol. 288, No. 10). In a journal article about the trial, authors claimed that “treatment with open carpal tunnel release surgery resulted in better outcomes than treatment than treatment with wrist splinting for patients with CTS (carpal tunnel syndrome).” Use a 0.01 significance level to test to the stated claim.
Contingency Table: Carpal Tunnel Syndrome
Hypotheses:
H0: Treatment outcome is independent of treatment option.
H1: Treatment outcome is dependent on treatment option.
Expected Values:
Complete the 2x2 table of expected outcomes (round values to 3 decimal places).
Explanation / Answer
applying chi square test on above data:
expected values are given in expected group in above:
test statistic: =9.75
crtiical values for abvoe 1 degree of freedom and 0.01 level = 6.63
as test statistic is above crtical value we reject null hypothesis
we have” sufficient evidence to support the claim that the treatment outcome is dependent on treatment option
(p<0.01)
Observed O successful not successful Total surgery 67 6 73 sprint 60 23 83 Total 127 29 156 Expected E=rowtotal*column total/grand total successful not successful Total surgery 59.429 13.571 73 sprint 67.571 15.429 83 Total 127 29 156 chi square =(O-E)^2/E successful not successful Total surgery 0.9644 4.2233 5.188 sprint 0.8482 3.7145 4.563 Total 1.813 7.938 9.750