Question

Sample surveys on sensitive issues can give different results depending on how the question is asked. A University of Wisconsin study divided 2400 respondents into 3 groups at random. All were asked if they had ever used cocaine. One group of 800 was interviewed by phone; 177 said they had used cocaine. Another 800 people were asked the question in a one-on-one personal interview; 208 said "Yes." The remaining 800 were allowed to make an anonymous written response; 218 said "Yes."

Are there statistically significant differences among these proportions?

Carry out a chi-square test for association between education level and opinion about astrology. Test H0:H0: the proportion of people who admit cocaine use is the same for all three interview methods versus Ha:Ha: the proportions are not the same (interview type makes a difference). Use α=0.01α=0.01.

χ2=

P=

Pick one:

There is no evidence that interview type makes a difference

There is evidence that interview type makes a difference

Answer 1