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

Full question attached

A. 230.4

B. 3.23

Explanation:

1. if 78.26% of murders are committed with firearms, 300 murders selected at random would be expected to have been committed with 300*0.7826= 230.4 firearms

2. To find how unusual this figure is, we find standard deviation from the mean 230.4

Standard deviation = x-u/N

=254-230.4/7.311= 3.23 rounded

Therefore 254 is unusual

7.311 is calculated √np(1-p)

because they could drop even lower..