A large clinical trial of the effect of diet on breast cancer assigned women at random to either a normal diet or a low fat diet To check that the random assignment did produce comparable groups we can compare the two groups at the start of the study Asked if there is a family history of breast cancer 840 of the 6318 women in the low fat group and 590 of the 5417 women in the control group said Yes If the random assignment worked well there should not be a significant difference in the proportions with a family history of breast cancer How significant is the observed difference State Is there evidence of a difference in the proportion of women with a family history of breast cancer between the treatment and control groups Plan Let p be the proportion for the treatment group and p2 the proportion for the control group State the hypotheses for your test Ho P P2 Ha P1 P2 Solve Give the value of the test statistic Use the calculator Select an answer What is the P value for the test What do you conclude O There is evidence that the two proportions differ at the 0 10 significance level The difference between the sample proportions is not significant at the 0 10 level The data prove that the null hypothesis is true That is the randomization worked