posted by Yuls
Each morning your alarm goes off. There is a 22% chance that you will not wake up and consequently be late for your 9am class. For the first 8 classes of the term, determine the probability that you will be ....
a) late exactly 3 times ____
b.) on time for every class ____
c) lat more than 3 times ____
d.) late at least 3 times but not more than 5 times ___
e.) suppose you were late for the first two classes. what is the probability than you will be late exactly three times?
f.) suppose you were late for the first two classes. What is the probability than you will be late more than 3 times?
Your questions fall in the category of binomial distribution
I will do the first two, you do and then show me how you did the others.
a) prob(wake up) = .78
prob(not wake up) = .22
prob(not wake up exactly 3 times out of 8)
= C(8,3) (.22^3)(.78^5)
= ..17216 , rounded off to 5 decimal places
b) prob(wake up 8 out of 8 times)
c) late more than three times
= late 4 times + late 5 times + ...+ late 8 times
= 1 - (late none + late 1 + late 2 + late 3)