I entered all data correctly in data function of the calculator and i applied the formula of sample variance which is summation of (x-xbar)^2/n-1.
(44-11)^2/4-1 which is coming out to 363.
p.s. answer mentioned in image is variance of x= 97.67 (0.9767)
variance of y= 82.67 .
covariance -83.33
why my answer is coming out be wrong?
X bar is 7.5 not 11. I think you have mistakenly added the last observation of x. The observation is -7 but if you add it you will get 11 which is wrong.
I did it in the calci and my answer is coming.
What answer did you get for Covariance ?
-83.3333
Yes! Okay. It’s matching. Thanks.
r kya hai bhai yaha?
do we need to find covariance by r or the conventional formula?
r= -0.9274
ok so r wan;t provided to us but we calculated it from calci. got it. thanks
Thank you! got it.
You dont need to calculate this by using formula. You can do this on calci. Follow these steps
1)press 2ND – 7 – 2ND – clear [to clear previous data – this is important step otherwise your ans will come wrong]
2)press 2ND – 7 – then fill these values :-
X01 = 10 – press enter – press arrow down key
Y01 = 2 – press enter – press arrow down key
X02 = 12 -press enter – press arrow down key
Y02 = minus 8 – press enter – press arrow down key
X03 = 15 – press enter – press arrow down key
Y03 = minus 6 -press enter – press arrow down key
X04 = minus 7 – press enter – press arrow down key
Y04 = 12 – press enter – press arrow down key
Then press 2ND – 8 – PRESS ARROW DOWN 3 TIMES AND GET Sx = 9.882645
Then press arrow down key again 3 times and get Sy = 9.092121
Now variance = (S.D)^2
THEREFORE,
VARIANCE OF X = (9.882645)^2 = 97.67
VARIANCE OF Y = (9.092121)^2 = 82.67
HOPE THIS HELPS
Thanks! got it.
also how to calculate cov(X,y)=-83.33?
Keep pressing arrow button down you will get r also..
Then multiply (r) * (s.d of x) * (s.d of y)
where r = -0.927428
s.d of x = 9.882645
s.d of y = 9.092121
you will get the answer
THANK YOU!!