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A survey was conducted from a large group of high school students in an effort to determine what science courses they were currently enrolled in.
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It was found that 77 % of the students were in chemistry, 70 in physics, and 48 % in biology.
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Find the following probabilities, assuming independence.
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So let's start with the probability that they are in chemistry and physics.
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So i'm going to look at the chemistry.
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They would give it to us in percentages.
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So i'm going to go ahead and change those to decimals.
00:34
So for chemistry and physics, i'm going to take the probability of chemistry and multiply it by the probability of physics.
00:42
So that's going to be chemistry.
00:44
It's going to be 0 .77.
00:46
Physics is 0 .7.
00:48
So all we have to do is multiply those two together.
00:51
I'll go do the calculator work all at one time later.
00:55
So in the next one, they want the probability theory theory theory, but not chemistry.
00:59
So this symbol means not chemistry.
01:03
So i'm going to have the probability of physics times the probability of not chemistry.
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So the probability of physics is 0 .7.
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The question is, what is the probability that they're not in chemistry? well, let's look at that.
01:19
77 % are in chemistry.
01:22
That means the other 23 % are not in chemistry.
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How did i get that? 100 minus 77 is 23%.
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So the ones that are not in chemistry are going to be 23 % or .23.
01:38
So that would be here.
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And then i would multiply those together and i would get my answer...