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Males and females are observed to react differently to a given set of circumstances.
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It's been observed that 70 % of the females react positively to these circumstances where only 40 % of the males react positively.
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Of the 20 people, 15 females and 5 males were subjected to these circumstances and they were asked to describe their reactions.
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Find the probability that a response picked randomly from the 20 is now.
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So i'm going to start.
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I've started a tree diagram here and i want to know male, female, what's the probability of actually picking a male versus a female? so the probability of a female is going to be 15 out of 20.
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And a probability of a male is going to be 5 out of 20.
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Since we have the other in percentages which we're going to convert to decimals, i'm going to go ahead and put these as a decimal.
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So 15 divided by 20 is going to be 0 .75, and this will be 0 .25.
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So the probability of a female is 0 .75, which i'm going to put here, 0 .75, and the male is 0 .25, which i'll put here.
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Now i'm going to go back to my question, and it says 40 % of the males react positively.
01:24
So that's going to be a 40 % going to the positive, which means we're going to have 60 % going.
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To the negative.
01:32
Then for the females it says 70 % react positively, and therefore we're going to have 30 % negatively.
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Now that we have this information, we can see what we need.
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So i'm going to come over here and get my black pen back.
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So we want to know the probability of a negative.
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Probability of a negative...