A study is designed to investigate gate whether there is a difference in response to various treatments in patients with rheumatoid arthritis . The outcome is patient's self -reported effect of treatment . The data are shown below . Is there a statistically significant difference in the proportions of patients who show improvement between treatments I and 2 . Apply the test at a 5 % level of significance 1 . Critical value ( 2 points ) 2 . Computed statistic ( 2 points ) 3 . Based on comparing the computed statistics to the critical value which of the following is ( are ) true ? ( 6 points ) a . There is significant evidence , alpha - 0 05 , to show that there is a difference in the proportions of patients who show improvement between treatments I and 2 b . There is not significant evidence , alpha = 0.05 , to show that there is a difference in the proportions of patients who show improvement between treatments I and 2 C . There is significant evidence , alpha = 0 05 , to show that there is a no difference in the proportions of patients who show improvement between treatments I and 2 d a and c