Question

The table below contains data on individual’s usage of a social media platform. It categorizes the data on the age range of the individual and their reported usage level. Use this table to answer the question that follows it.

	Low	Moderate	High
18-30	286	592	464
31-55	209	438	381
56+	254	237	139

What is the probability that a randomly selected individual reports a low usage level, a moderate usage level, or both?

Answer 1

Probability of event = number of outcomes favourable to event / total number of outcome

a)Given: Total number of people = 3000, total of individual with low usage level = 749.

Probability of individual with low usage level = total number of low usage level individual / Total number of people

=749 / 3000

= 0.250

Probability that a randomly selected individual report a low usage is 0.250

b) Given: Total number of people = 3000, total of individual with moderate usage level = 1267.

Probability of individual with moderate usage level =

Total number of moderate usage level individual / Total number of people

=1267 / 3000

= 0.422

Probability that a randomly selected individual report a moderate usage is 0.422

c) Given: Total number of people = 3000, total of individual with low and moderate usage level = 2016 (749+1267 =2016)

Probability of individual with low or moderate usage level =

Total number of low and moderate usage level individual / Total number of people

=2016 / 3000

= 0.672

Probability that a randomly selected individual report a low or moderate usage is 0.672

Another way :

Probability of individual with low or moderate usage level = Probability of low usage + probability of moderate usage

                                =0.250+0.422         (from a and b)

                                =0.672