Part of the population of 6,250 elk at a wildlife preserve is infected with a parasite. A random sample of 50 elk shows that 6 of them are infected. How many elk are likely to be infected? Based on the sample, there will likely be infected elk in the wildlife preserve.

Explanation:

6 in the sample of 50 are infected, so 6/50 = 12/100 = 12% are infected in the sample. We expect this percentage to carry over to the entire population assuming we picked a representative random sample that isn't biased.

12% of 6250 = 0.12*650 = 750 is the expected number of infected individuals in the population.

Here's an alternative way you can solve through a proportion

(number infected)/(total) = (number infected)/(total)

6/50 = x/6250

6*6250 = 50x ... cross multiply

37500 = 50x

50x = 37500

x = 37500/50 ... divide both sides by 50

x = 750