this question is taken from my statistics assignment homework

Cocaine addiction is difficult to overcome.Addicts have been reported to have a significant depletion of stimulating neurotransmitters and thus continue to take cocaine to avoid feelings of depression and anxiety.A 3-year study with 72 chronic cocaine users compared and antidepressant drug called desipramine with lithium and a placebo. (Lithium is the standard drug to treat cocaine addiction.A placebo is a substance containing no medication, used so that the effect of being in the study but ot taking any drug can be seen.)One-third of the subjects, chosen at random, received each treatment.Following are the results:

Treatment

Cocaine relapse?

Yes

No

Desipramine

10

14

Lithium

18

6

Placebo

20

4

(a) (2 Points)Compare the effectiveness of the three treatments in preventing relapse using percents and a bar graph.write a brief summary

(b) (1 point)Can we comfortably use the chi-square test to test the null hypothesis that there is no difference between treatments?Explain.

(c) (2 points) Perform the significance test and summarize the results.