P(Verizon) = (Number of people with Verizon)/(Total number of people) = 90/400 = 0.225
P(iPhone) = (Number of people with iPhone)/(Total number of people) = 185/400 = 0.463
P(Verizon|iPhone) = (Number of people with iPhone and Verizon)/(Number of people with iPhone) = 50/185 = 0.270
P(iPhone|Verizon) = (Number of people with iPhone and Verizon)/(Number of people with Verizon) = 50/90 = 0.556
The events "iPhone" and "Verizon" are not independent because P(Verizon|iPhone) is not equal to P(Verizon) and P(iPhone|Verizon) is not equal to P(iPhone).
A survey is taken of 400 people asking what type of cell phone they own and what cell phone carrier they use. The results are shown in the table below.
Carrier
Phone Type Verizon T-Mobile AT&T
Total
Android 40 110 65 215
iPhone 50 65 70 185
Total 90 175 135 400
Find the following probabilities from the given table. Probabilities should be written as decimals rounded to 3 decimal places.
P(Verizon) =
P(iPhone) =
P(Verizon|iPhone) =
P(iPhone|Verizon) =
Are the events “iPhone” and “Verizon” independent?
1 answer