Question

The American Society for Microbiology (ASM) and the Soap and Detergent Association (SDA) jointly commissioned two separate studies during 2007, both of which were conducted by Harris Interactive. In one of the studies 1001 adults were interviewed by telephone and asked about their hand washing habits. In the other study, the hand washing behavior of 6706 adults was inconspicuously observed within public restrooms in four U.S. Cities.

a) In the telephone interviews, 921 of the adults said they always wash their hands in the restrooms. Use this result to find
the point estimate for the proportion of adults who say they always wash their hands.
b) Verify that the requirements for constructing the confidence interval for ? from part (a) are satisfied.
c) Using the results from the telephone interviews, construct and interpet a 95% confidence interval for the proportion of
adults who say they always wash their hands in public restrooms.
d) Is it possible that the proportion of adults who say always wash their hands in public restrooms is less than 0.85? Is this
likely? Explain.
e) In the observational study, 4679 of the 6076 adults were observed washing their hands. Use this result obtain the point
estimate for the proportion for the proportion of adults who was their hands in a public restroom.
f) Verify that requirements for constructing a confidence interval for ? from part e are satisfied.
g) Using the results from the observational study construct and interpret a 95% confidence interval for the proportion of
adults who wash their hands in public restrooms.
h) Is it possible that the proportion of adults who wash their hands is greater than 85%? Is this likely? Explain. (3pts)
i) Based on your findings above, what might you conclude about the proportion of adults who say they always wash their
hands versus the population of adults who actually was their hands in public restrooms? Why do you think this is?

Answer 1