Question

Stats help:
Q.The mean of 12 observations is 3704.One more observation is added and the mean becomes 37.5.Find the value of new observation.

Answer 1

You can do it!

Answer 2

Find the total of the operations when there were 12.
Then find the total when there were 13.

Answer 3

What is the difference?

Answer 4

Since \[
Average = \frac{Total}{Observatioins}
\]Then \[
Total = Average \times Observations
\]

Answer 5

find the sum
\[\sum x_i=
\bar{x}n\]

Answer 6

\[MEAN x=\frac{ \sum_{}^{}x }{ n }\]
total of 12 observations=37.06*12
total of 13 observations=37.5*13
13th observation=? (subtract and find)

Answer 7

lets call the new observation x
\[\bar{x}_2=\frac{\bar{x}_1+x}{n+1}\\\bar{x_1}=37.06,\bar{x}_2=37.5,n+1=13\]

Answer 8

I solved the whole question with LatEx and it crashed....

Answer 9

i mean\[\bar{x}_2=\frac{\bar{x}_1n+x}{n+1}\]
\[x=n(\bar{x}_2-\bar{x}_1 )+\bar{x}_2\]

Answer 10

I know..I was doing it myself but the page crashed..

Answer 11

I so pissed off right now..

Answer 12

so you cant see anything in LaTex here

Answer 13

I know how to do this..i was typing it if i was write.I was at the end of it and it crashed....

Answer 14

ohhhhh bad...okay ...it does that sometimes ,i guess it has to be reported to the OS feedback

Answer 15

Let me do again..oh well.

Answer 16

Formula is
\[\bar{x} =\frac{ \Sigma x }{ n } \]
where n=15
and \[\bar{x} =3704\]

Answer 17

So,plugging in the formula
\[3704=\frac{ \Sigma x }{ 12 }\]

Answer 18

I mistyped above n=12.

Answer 19

Then,
\[\Sigma x =4448\]

let the value of one observation added be *y*
Using the same formula again

\[37.5=\frac{ 4448+y }{ 13 }\]

Answer 20

\[487.5=4448+y\]
\[y=4448-487.5\]
y=3960.

Answer 21

3960.5*

Answer 22

@wio Help me c:

Answer 23

What did you get for your totals?

Answer 24

What do you mean?

Answer 25

is it 37.04 or3704

Answer 26

3704.

Answer 27

\[
12\times 3706 = ?\\
13\times 37.5 = ?
\]

Answer 28

@wio it's 3704* and
12 x 3704=4448
and 13 x 37.5 =487.5

Answer 29

didnt you mean 37.06 or 3706

Answer 30

as you have calculated it should b e y=487.5-4448
which is negative

Answer 31

Omg sorry i typed wrong,Let me edit the question..Sorry :3

Answer 32

@surjithayer we subract the small number with the greater one...No?

Answer 33

kick your computer

Answer 34

@nincompoop not my computer's fault something is wrong with OS.Happend to many users.

Answer 35

i think total for 13 observation should be greater than total for 12 observations

Answer 36

start doing paid subscription :)

Answer 37

I don't think so @surjithayer because the other question i did at my class with my teacher the total for 16 observation was quiet less than the observation for 15..

Answer 38

uri, this is the same kind of help you received earlier.

Answer 39

your point?

Answer 40

you should be able to do this one if you understood the other one :P

Answer 41

So,didn't i just do it? I'm asking if i'm right..problem?

Answer 42

you had 6 earlier, now you have 12
then 1 is added on both that gave a new mean

Answer 43

o.k if total for 13 observationis less then 13th observation should be negative

Answer 44

(444.48+x)/13=37.5

here's how it is broken down without the fancy statistical jargon
37.04 x 12 = 444.48
multiply it back so you get the summation prior to the unknown. since there were 12 observations, you multiply your initial mean by 12.

now we need to find out the unknown (that is +1 observation) in order to get the mean of 37.5.
so that is 444. 48 + x
then divide it by the final number of observations, 13

(444.48 + x)/13 = 37.5

Answer 45

Nin it is 3704 not 37.04..

Answer 46

I think that's a typo LOL
but if it is really 3,704 then the same kind of process is required for you to find the unknown observation

Answer 47

Let me ask a friend

Answer 48

okay. it is weird that the new mean is wayyyyyyyyyyyy too low than the initial one. from thousands to tens

Answer 49

LOL NIN IT'S 37.4 NOT 3704.My sir doesn't know how to make a decimal point.He wasted my 1 hour..

Answer 50

lol told you so… my training in chemistry paid off

Answer 51

Omg now i know how to do it..xD

Answer 52

then it is 37.5*13-37.4*12

Answer 53

Let me solve and show. :P

Answer 54

yeah so I put 37.04, you just have to make the correction to 37.4

Answer 55

you're on the right track

Answer 56

Thanks :D

Answer 57

always ask your professor what he has written down so you're not wasting a lot of time calculating the wrong information.

Answer 58

everyone makes mistakes

Answer 59

I do that.I joined late and my class fellows have done this already i just took these photocopied questions from a classmate and did few at class..so didn't know that my teacher makes such a weird typo like WEIRD..0 except a decimal point.

Answer 60

@nincompoop look xD

Answer 61

lol
now you know that small circle is period

Answer 62

Lol yess

Answer 63

there is small circle on is also .you can corelate

Answer 64

any way you know the procedure to solve such problems.

Answer 65

:)