• 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)

A level Statistics doubt??Post your doubts here!

Messages
18
Reaction score
4
Points
13
when do we use 6.5 incase of fewer/ lesser than 7 and when do we use 7?
I am really confused about this
 
Messages
844
Reaction score
2,495
Points
253
when do we use 6.5 incase of fewer/ lesser than 7 and when do we use 7?
I am really confused about this

You use continuity correction when you use a continuous function to approximate a discreet one. Like when you use normal distribution to estimate a binomial. Example, In a sample of X data find the probability that < than 20 will have 51 feathers.
 
Messages
2,703
Reaction score
3,939
Points
273
You use continuity correction when you use a continuous function to approximate a discreet one. Like when you normal distribution to estimate a binomial. Example, In a sample of X data find the probability that < than 20 will have 51 feathers.
so that what its called i called it continuety correctivity :D
thats y my sir said it was wrong
 
Messages
18
Reaction score
4
Points
13
You use continuity correction when you use a continuous function to approximate a discreet one. Like when you use normal distribution to estimate a binomial. Example, In a sample of X data find the probability that < than 20 will have 51 feathers.

but how do i tell the difference between such type of questions...i have seen many problems where we are supposed to find the probability of fewer than 75(for e.g.) and we use (75-mean)/S.D. to calculate it...
my teacher told me that whenever we have to add or subtract 0.5...we are told to use normal approximation in the question...but this is not always the case...
 
Messages
2,703
Reaction score
3,939
Points
273
but how do i tell the difference between such type of questions...i have seen many problems where we are supposed to find the probability of fewer than 75(for e.g.) and we use (75-mean)/S.D. to calculate it...
my teacher told me that whenever we have to add or subtract 0.5...we are told to use normal approximation in the question...but this is not always the case...
cc is only applied where there is a conversion from binomial to normal
 
Messages
18
Reaction score
4
Points
13
cc is only applied where there is a conversion from binomial to normal
Thanks a ton...could you plz elaborate what you mean by conversion from binomial to normal...i am sorry i can do questions just fine but i don't really get what is meant by binomial, normal etc...can yu plz just give me an example question...i ll be very thankful..
 
Messages
844
Reaction score
2,495
Points
253
how do you find the s.d?
i got the ans but i did it in a much longer way...found the sum of xsquare first and then from there on got the rest
and also http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s12_qp_61.pdf
how to get the sd in 5iii
thanks for any help

2ii) for sd.=√ S(x − 100)^2/15 - (72/15)^2
=√10.24 = 3.2

Summer 12/61
mean is 8.34/9
for sd.= √ [(.76)^2 +(.85)^2+(.89)^2+(.91)^2+(.92)^2+(.94)^2+(.96)^2+(1.04)^2+(1.07)^2]/9 - (8.34/9)^2
=√(7.7984/9) - (8.34/9)^2 = .0882
 
Top