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# S1 edexcel watch

1. How do you do this question?
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2. (Original post by fullmetal heart)
How do you do this question?
We're not here to do your homework for you, please show some working or a smattering of your own thoughts concerning the question.
3. I'll start you off

Y~N (μ,σ2)

to find μ (mean) you do
4. (Original post by undercxver)
I'll start you off

Y~N (μ,σ2)

to find μ (mean) you do
Are you sure it's normally distributed?
5. (Original post by Zacken)
Are you sure it's normally distributed?
Discrete random variables.
6. I figured out the probabilities of the combinations and the sum of all the combinations, this meant that I could figure out the probabilities of getting a particular score. But I don't know what to do now?

UPDATE: I just remembered that I should use the formula for variance and then work out the standard deviation :P
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7. (Original post by fullmetal heart)

UPDATE: I just remembered that I should use the formula for variance and then work out the standard deviation :P
Yep standard deviation is just the square root of variance.
8. (Original post by Zacken)
Yep standard deviation is just the square root of variance.
Thanks, wow I can be thick sometimes, I literally just used that formula two questions ago
9. (Original post by fullmetal heart)
Thanks, wow I can be thick sometimes, I literally just used that formula two questions ago
No worries, glad you figured it out yourself!

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