You are Here: Home >< Maths

# S1 edexcel

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
1. How do you do this question?
Attached Images

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
Attached Images

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!

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: April 13, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams