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# Normal Distribution Help!!! S2 Watch

1. I am currently study OCR MEI S2.

When calculating normal distribution, such as X-(10, 3^2)
Calculate the probability of P(x<11)Z
=(11-10)/3=0.3333333333…

So it is P(z<0.333) or P(z<0.3333)?

For P(z<0.333) gives a probability of 0.6304
For P(z<0.3333( gives a probability of 0.6305. calculated through 6293+11+(3*4)/10 (Interpolation).

Can someone give me advice whether to use 3 decimal places or 4 decimal places for P(z<0.333) or P(z<0.3333)?

Many thanks.
2. (Original post by Student6000)
I am currently study OCR MEI S2.When calculating normal distribution, such as X-(10, 3^2)Calculate the probability of P(x<11)Z=(11-10)/3=0.3333333333So it is P(z<0.333) or P(z<0.3333)?For P(z<0.333) gives a probability of 0.6304For P(z<0.3333( gives a probability of 0.6305. calculated through 6293+11+(3*4)/10 (Interpolation).Can someone give me advice whether to use 3 decimal places or 4 decimal places for P(z<0.333) or P(z<0.3333)?Many thanks.
I think the mark schemes often use 4 but it says you can also be awarded the marks for 3. Our teacher told us to just use 3 as it saves time but I'd like to see what other people have to say...
3. (Original post by Alex621)
I think the mark schemes often use 4 but it says you can also be awarded the marks for 3. Our teacher told us to just use 3 as it saves time but I'd like to see what other people have to say...
On the mark scheme they use 3 decimal places. The most recent one also uses 3 d.p. I haven't seen any paper that uses 4 d.p.

I asked my teacher today and he said its fine to use either, but the 4d.p is more accurate. But 3d.p is completely fine and save time.

And yh, I wanna see what other people say too
4. (Original post by Student6000)
On the mark scheme they use 3 decimal places. The most recent one also uses 3 d.p. I haven't seen any paper that uses 4 d.p.

I asked my teacher today and he said its fine to use either, but the 4d.p is more accurate. But 3d.p is completely fine and save time.

And yh, I wanna see what other people say too
Jan 2013 Q2ii uses 4
So does June 2014 3iii
5. (Original post by Alex621)
Jan 2013 Q2ii uses 4
So does June 2014 3iii
Oh yeah. I didn't see that.

That doesn't help 😩. I don't know how many decimal spaces to use now.

But on the side of the mark scheme for June 14 3iii, it says "allow 0.1145" which is derived from 3d.p.

But still confused how many d.p to use.
6. (Original post by Student6000)
Oh yeah. I didn't see that.

That doesn't help 😩. I don't know how many decimal spaces to use now.

But on the side of the mark scheme for June 14 3iii, it says "allow 0.1145" which is derived from 3d.p.

But still confused how many d.p to use.
Haha I don't know either and my teacher doesn't know so I'm going to just use 3.

We never got taught how to use 4 so even if you are supposed to use 4, I won't be able to 😒 I have no clue how you do it

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