According to a report, 67.5% of murders are committed with a firearm. (a) if 200 murders are randomly selected, how many would we expect to be committed with a firearm? (b) would it be unusual to observe 153 murders by firearm in a random sample of 200 murders? why?

The answer is 135 murders.

Step-by-step explanation: The report tells us that statistically 67.5% of murders are committed using a firearm. It follows therefore that in a sample of 200 randomly selected murders, one would expect that 67.5% of those would be by a firearm. * 200 = 135.

It would certainly be higher that the expected value based on previous data collected but it would not be unusual because one sample may have a higher than "normal" amount of murders by firearm. Statistics aren't going to be exact for every sample.