Reference no: EM132853322

Following is a contingency table showing the results of a diagnostic blood test (POS=positive; NEG = negative) to whether or not a woman's fetus is affected with Down syndrome. The study is based on the results from 5282 women aged 35 or over.

Blood test

Disease status                                 POS       NEG      Total

Affected (A)                                     48           6           54

Not affected  (NA)                         1307     3921     5228

Total                                                  1355      3927    5282

(A)  Let us try to answer the following

Questions:

• What is the probability that a woman will have a positive test result i.e P(POS)?
• What is the probability that a woman has Down syndrome i.e P(A)?
• What is the probability that a woman has Down syndrome and tests positive i.e P(A and POS)?
• Are the events "POS" and "A" independent or dependent?