Chapter 23

The variance of the first 50 even natural numbers is (A) \(\frac{833}{4}\) (B) 833 (C) 437 (D) \(\frac{437}{4}\)

The mean of the data set comprising of 16 observations is 16 . If one of the observation valued 16 is deleted and three new observations valued 3,4 and 5 are added to the data, then the mean of the resultant data, is (A) \(16.0\) (B) \(15.8\) (C) \(14.0\) (D) \(16.8\)

If the standard deviation of the numbers 2,3, a and 11 is \(3.5\), then which of the following is true? (A) \(3 a^{2}-23 a+44=0\) (B) \(3 a^{2}-26 a+55=0\) (C) \(3 a^{2}-32 a+84=0\) (D) \(3 a^{2}-34 a+91=0\)