Interpolation - check where i'm going wrong?Watch

#1
Ah every question on interpolation i get wrong, no matter how hard i try to get it, so would really help if you could tell me where i'm going wrong.

e.g. (example made up by me)

x ....... F
0-5....... ... 3
5-9 ...... ... 7
10-14 ....... 9
15-19 ....... 5

So median value is 12th value : so in the 10-14 class

it's 2 of the way along in that class so 9/5 = 1.8 x 2 = 3.6

therefore 3 + 7+ 3.6 = 13.6
so the median is 13.6 right/wrong

OR another way is using the equation

b + {(1/2n - f) / fc} x c

where b: lower class boundary of median class
f: sum of all freq below median class
fc: freq of median class
c: width of median class.

9.5 + {(12 x 10) / 9} x 5 = 161.666 WHAT

As you can see i need help!
0
12 years ago
#2
dude what the hell are u doing, sloppy sloppy
0
#3
you could at least help? So what am i doing wrong?
0
12 years ago
#4
even the calculation uve written is calculated wrong

9.5 + (1/2 x 25-10)/9 x 5 = 13 2/3

type the brackets in your caculator first .5 x 7.5 then multiply by 5 then add 9.5
0
12 years ago
#5
is the answer 10/9 + 9.5
0
12 years ago
#6
for the median that is
0
#7
Footballhead thanks for the help, so i got it right the first way?

The second way i did times it buy 5 then add 9.5 i just couldnt write it out like that.

OMG i just figured out how you did it (took me a while): you take 1/2 (n-f) not (1/2 x n) - f ?
Am i right...
panicing now..
0
12 years ago
#8
ok crap what did i do wrong
0
12 years ago
#9
did i get the answer right mate?

page 33 of ure s1 book

,median = b + (1/2 n - f/ fm) x w

so if u wanna find the q1 would u use 1/4n??
0
12 years ago
#10
am i rite? lol whose rite???
0
#11
I dont know what the answer is, i was asking you to work it out!!
I'll try again tomorrow!
0
12 years ago
#12
this is what happens when they let us idiots take stats!!!
0
12 years ago
#13
i think my answer is correct
0
12 years ago
#14
answer is 13.6 (or 13 2/3)

And i dont even have to do any calculations to tell that; you can tell from the table given.
duh!
0
12 years ago
#15
?????? isn;t it 9.5+(12- 10 / 9) * 5

and that gves 10/9 + 9.6
0
12 years ago
#16
yeh wt u on about 13. 6 lol?????
0
12 years ago
#17
i meant 10/9 + 9.5
0
12 years ago
#18
I got 10.611
0
12 years ago
#19
exactly................nice one dev u mite wanna do sum calculations next time
0
12 years ago
#20
Oh and can anyone explain how you done calculations witjout using formula? Or just say how is called that thing or topic.
0
X

new posts
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.

University open days

• Cranfield University
Cranfield Forensic MSc Programme Open Day Postgraduate
Thu, 25 Apr '19
• University of the Arts London
Open day: MA Footwear and MA Fashion Artefact Postgraduate
Thu, 25 Apr '19
• Cardiff Metropolitan University
Sat, 27 Apr '19

Poll

Join the discussion

Have you registered to vote?

Yes! (427)
37.79%
No - but I will (87)
7.7%
No - I don't want to (76)
6.73%
No - I can't vote (<18, not in UK, etc) (540)
47.79%