(D)22ixxn30.The mean of 100 observations is 50 and their standard deviation is 5. The sumof all squares of all the observations is(A)50000(B)250000(C)252500 (D) 25500031.Let a, b, c, d, ebe the observations with mean mand standard deviation s.The standard deviation of the observations a+ k, b+ k, c+ k, d+ k, e+ kis(A)s(B)k s(C)s + k(D)sk32.Let x1, x2, x3, x4, x5be the observations with mean mand standard deviation s.The standard deviation of the observations kx1, kx2, kx3, kx4, kx5is(A)k+ s(B)sk(C)k s(D)s33.Let x1, x2, ... xnbe nobservations. Let wi= lxi+ kfor i= 1, 2, ...n, where land kare constants. If the mean of xi’sis 48 and their standard deviation is 12,the mean of wi’sis 55 and standard deviation of wi’sis 15, the values oflandkshould be(A)l= 1.25, k= – 5(B)l= – 1.25, k= 5(C)l = 2.5, k= – 5(D)l= 2.5, k= 534.Standard deviations for first 10 natural numbers is(A)5.5(B)3.87(C)2.97(D)2.8735.Consider the numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. If 1 is added to each number,the variance of the numbers so obtained is
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