(This continues exercise 9.)

(a) To show that screening reduces the risk from breast cancer, someone wants to compare 1.1 and 1.5. Is this a good comparison? Is it biased against screening? For screening?

(b) Someone claims that encouraging women to come in for breast cancer screening increases their health consciousness, so these women take better care of themselves and live longer for that reason. Is the table consistent or inconsistent with the claim?

(c) In the first year of the HIP trial, 67 breast cancers were detected in the

"examined" group, 12 in the "refused" group, and 58 in the control group.

True or false, and explain briefly: screening causes breast cancer. plo47