Not all telephone polls carried out to estimate
voter or consumer preferences make calls to cell
phones. one reason is that in the usa, automated
calls ("robocalls") to cell phones are not
permitted and interviews conducted by humans
are more costly.
a. how might the strategy of leaving out cell
phones affect the goal of obtaining a random
sample of voters or consumers?
b. which criterion of random sampling is most
likely to be violated by the problems you
identifi ed in part (a): equal chance of being
selected, or the independence of the selection
of individuals?
c. which attribute of estimated consumer preference
is most affected by the problem you
identifi ed in (a): accuracy or precision?

Aresearch study is studying the effects of a new drug for osteoporosis alzheimer's disease (ad) for women above the age of 65 years. a group of individuals with osteoporosis is randomized into two groups. one group is treated conventionally, and the second group is treated with the new medication. assessments are made at 3, 6, 12, 36, and 48 months. the conventionally treated group is assessed for ad using a serum blood test, and the treatment group is assessed for ad using a pet radiotracer that binds to beta-amyloid plaques. in comparing these 2 trial arms, the authors of the study may encounter which type of bias? a. selection bias on the risk of developing b. measurement bias c. confounding bias d. recall bias e. lead-time bias