Customers lose their bags 8% of the time at airports.

20 random people were watched to see if their bags were lost. Whats the probability that at least 18 of them lost their bags?

1 answer

at least 18 lost their bags
implies
18, 19 or 20 lost their bags.

prob of losing bag = .08
prob of not losing bag = .92

prob as stated
= C(20,18)(.08)^18 (.92)^2 + C(20,19)(.08)^19 (.92) + .08^20
= ....

you do the button-pushing