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If and , then the standard deviation of the items is
detailed solution
Correct option is B
We have, ∴ ∑i=19 xi−5=9 and ∑i=19 xi−52=45⇒ ∑i=19 xi−45=9 and ∑i=19 xi2−10xi+25=45 ⇒ ∑i=19 xi=54 and ∑i=19 xi2−10∑i=19 xi+25×9=45⇒ ∑i=19 xi=54 and ∑i=19 xi2−10×54+225=45⇒ ∑i=19 xi=54 and ∑i=19 xi2=360∴ Variance =19∑i=19 xi2−19∑i=19 xi2⇒ Variance =3609−5492=40−36=4Hence, standard deviation =4=2. ALITER Let the variable U take values u1,u2,…,u9 such that ui=xi−5,i=1,2,…,9. Then U¯=X¯−5 and Var(U)=Var(X)Now, Var(U)=19∑i=19 ui2−19∑i=19 ui2 =19∑i=19 xi−52−19∑i=19 xi−52=459−992=5−1=4∴ σU=Var(U)=2Talk to our academic expert!
Similar Questions
For (2n + 1) observations , and 0, where all x's are distinct, let SD and MD denote the standard deviation and median, respectively. Then which of the following is always true?
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