In a randomized clinical trial. 154 women with breast cancer were assigned to receive chemotherapy. Another 164 women were assigned to receive chemotherapy combined with radiation therapy. Survival data after 15 years are given in the following table. Use these data to conduct a test of the null hypothesis that type of treatment does not affect survival rate.

Here is computer output for a chi-square test.
X-squared = 3. 47, df = 1, p-value = 0. 0625
(a) Compute the sample proportions.
(b) Compute the expected frequencies.
(c) If α = 0.05, what is your conclusion regarding H0?
(d) Suppose a directional alternative that the addition of radiation therapy enhances survival had been used. In this case what would be your conclusion regarding H0?

Transcribed Image Text:

Chemotherapy only 78 76 154 Chemotherapy and radiation therapy Died Survived Total 98 164