• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Statistics S1 Doubts

Messages
283
Reaction score
506
Points
103
Messages
28
Reaction score
9
Points
3
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w12_qp_63.pdf

Guys help!
In Q(5) (iii) when finding the value of k, why does z>0.445 become P(z<k) - P(z<0.445) in the next step? I mean, why is it becoming <0.445 when it should >?
Is there any technique or explanation I am missing?

P(87<X<k) = 0.3
P(X<87) = 0.6718 (From the previous question)
P(X<k)= P(X<87) + P(87<X<k) = 0.6718+ 0.3= 0.9718
P(Z<=(k-82)/root 126) = 0.9718
(k-82)/root 126 = 1.906 or (1.907)
k-82= 21.4
k= 103.39= 103 (3sf)

AND it was never greater than it is less than. Read the question again.
 
Messages
134
Reaction score
30
Points
38
we
P(87<X<k) = 0.3
P(X<87) = 0.6718 (From the previous question)
P(X<k)= P(X<87) + P(87<X<k) = 0.6718+ 0.3= 0.9718
P(Z<=(k-82)/root 126) = 0.9718
(k-82)/root 126 = 1.906 or (1.907)
k-82= 21.4
k= 103.39= 103 (3sf)

AND it was never greater than it is less than. Read the question again.
we dont have to find see normal table for k value?? i mean 0.3??
 
Messages
309
Reaction score
210
Points
53
1st - 48C43
2nd - 6! x 5!
- 6! x 7P4
3rd - 1/324
- 0.0212
4th - Tree diagram
- E(X) = 2 attempts
5th - P(X<8) was easy to find
- q was 7.74
- P(X<4 mean) = 1 - P(X<2)
6th - cumulative frequency graph
- h = 15.6 cm or 21.5 cm (not sure)
- SD = 6.01
7th - binomial distribution (4<=X<=6)
- Normal distribution P(X<114.5) dont remember
- np > 5 and nq >5
 
Messages
216
Reaction score
334
Points
73
omg yes i got 1 wrong but 2 was all correct al7amdulillah and what did u guys get for cmmulative freqency height? i got 16cm
 
Top