Question

Find the indicated probability. Round to the nearest thousandth. In a blood testing procedure, blood samples from 6 people are combined into one mixture. The mixture will test neg if all samples are neg. If the probability that an individual sample tests positive is 0.11, what is the probability that the sample will test ?

Answer 1

The mixture will test negative if the 6 individuall samples are negative.

Ther probability that one sample is negative is independent of the probabilities of the other samples.

Then, the probability of the six combined events (all negative) is equal to the product of the probabilities for each sample (each negative).

The probability for one sample to be negative is 1 - 0.11 = 0.89.

Then, the combined probability is [0.89]^ 6 = 0.497  ≈ 0.50

Answer: 0.50