# statistics question

Watch
Announcements
#1
could you give me a clue or two to start.
0
#2
0
1 month ago
#3
(Original post by sonal7)
What sort of distribution are you using?
0
#4
(Original post by mqb2766)
What sort of distribution are you using?
i think its geometric. then binomial.I have 'done it' but my answer does not match.

i got x^5= 0.951
so x=-.98 but the ans book says x=0.99

then i got that p =1-0.98 which 0.02 but the ans book 0.01

x~B(1000,0.02) whereas the ans book says B(1000,0.01).

so my mean is np which is 20 and the ans is supose to be 10?

HELP
Last edited by sonal7; 1 month ago
0
1 month ago
#5
(Original post by sonal7)
could you give me a clue or two to start.
part b) mentions using a Poisson approximation iirc. so that should give you an idea with how to begin.
0
#6
(Original post by the bear)
part b) mentions using a Poisson approximation iirc. so that should give you an idea with how to begin.
i was only doing part a) when i got stuck but thanks need to move on.
0
1 month ago
#7
(Original post by sonal7)
i think its geometric. then binomial.I have 'done it' but my answer does not match.

i got x^5= 0.951
so x=-.98 but the ans book says x=0.99

then i got that p =1-0.98 which 0.02 but the ans book 0.01

x~B(1000,0.02) whereas the ans book says B(1000,0.01).

so my mean is np which is 20 and the ans is supose to be 10?

HELP
Check the root of 0.951?
Last edited by mqb2766; 1 month ago
1
1 month ago
#8
(Original post by sonal7)
i think its geometric. then binomial.I have 'done it' but my answer does not match.

i got x^5= 0.951
so x=-.98 but the ans book says x=0.99

then i got that p =1-0.98 which 0.02 but the ans book 0.01

x~B(1
000,0.02) whereas the ans book says B(1000,0.01).

so my mean is np which is 20 and the ans is supose to be 10?

HELP
0.9510.2= 0.99000207164
1
#9
(Original post by the bear)
0.9510.2= 0.99000207164
I dont get this at all then.
0
#10
(Original post by mqb2766)
Check the root of 0.951?
That makes sense. It 0.99 phew!!! I have an additional favour to ask. Edexcel have released some papers but I cant work out which one They are . I am doing DM and S1 options.

https://qualifications.pearson.com/e...s-for-students
0
1 month ago
#11
Sorry cant give a definitive answer.
A useful (binomial) approximation when x is small is
(1-x)^n = 1 - nx
This fits nicely with this question x=0.01, 1-nx=0.95.
Last edited by mqb2766; 1 month ago
0
#12
(Original post by the bear)
0.9510.2= 0.99000207164
i got this. thanks for the correction!
1
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### Do you think receiving Teacher Assessed Grades will impact your future?

I'm worried it will negatively impact me getting into university/college (27)
38.57%
I'm worried that I’m not academically prepared for the next stage in my educational journey (6)
8.57%
I'm worried it will impact my future career (4)
5.71%
I'm worried that my grades will be seen as ‘lesser’ because I didn’t take exams (21)
30%
I don’t think that receiving these grades will impact my future (7)
10%
I think that receiving these grades will affect me in another way (let us know in the discussion!) (5)
7.14%