Question

Based on pretrial speculation, the prob that a jury will return a guilty verdict in a certain high-profile murder case is thought to be 15% if the defense can discredit the police department, and 80% if they cannot. Veteran court observers believe that the skilled defense attorneys have a 70% chance of convincing the jury that the police either contaminated or planted some of the key evidence. What is the probability that the jury returns a guilty verdict?

Answer 1

Answer:

34.5% probability that the jury returns a guilty verdict

Step-by-step explanation:

We have these following probabilities:

The defense attorneys have a 70% chance of convincing the jury that the police either contaminated or planted some of the key evidence.

In this case, there is a 15% probability that the jury will return a guilty verdict.

There is also a 100 - 70 = 30% of not convincing the jury that the police either contaminated or planted some of the key evidence.

In this case, 80% probability of the jury returning a guilty verdict.

What is the probability that the jury returns a guilty verdict?

15% of 70% and 80% of 30%. So

$p = 0.15*0.7 + 0.8*0.3 = 0.345$

34.5% probability that the jury returns a guilty verdict