78.2% of the students study more that one day for the chapter test. Find the probability that a randomly selected student did not study more than one day for the test.

Question

eviant · Answer

@Vocaloid

Vocaloid · Answer

P(not A) = 1 - P(A)

Try to apply this logic to your problem

eviant · Answer

what's A?

Vocaloid · Answer

Re-read the problem

Notice you are given a probability of some event (A) happening and asked to find the probability of A not happening

Vocaloid · Answer

A is just a variable used to represent an event

Vocaloid · Answer

There are only two possibilities

1. A student does study more than an hour a day
2. A student does not study more than an hour a day

Therefore

P(students who did not study) = 1 - P(students who did study)

Vocaloid · Answer

Since all probabilities for a given event add up to 1

Vocaloid · Answer

You are told that the portion of students who study is 78.2% or .782

So the probability of students who don’t study is 1 - 0.782