Question

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?

Answer 1

Answer: 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. $\frac{67.5}{100}$ * 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.