Answer the following questions using the information given in the table below. The table is based on the assumption that2%of breast tumors are malignant. This table also assumes that mammogram screening is80% accurate.

Tumor Is Malignant Tumor Is Benign Total

Positive Mammogram 640 7,840 8,480

Negative Mammogram 160 31,360 31,520

Total 800 39,200 40,000

The first two answers below shouldbe percentages rounded to the nearest tenth of a percent.

Suppose the patient has a positive mammogram. What is the chance that she really does have cancer?

%

What is the chance of a positive mammogram, given that the patient has cancer?

%

Suppose a patient has a negative mammogram.What is the chance that she actually has cancer?Give this answer as a percentage rounded to two decimal places.

%

What is the chance of a positive mammogram, given that the patient does not have cancer?Answer with a percentage rounded to the nearest tenth.

%