IM using my brothers account with his permission of course and so Im kinda stuck on these questions from 14 a)ii) downwards
thanks
After some small effort I was able to read your questions. For future reference: When you want help from someone, you make things as easy as possible for that person. In this instance, that would mean typing your questions out.
14 a. (ii) Substitute the data into the usual formula that is sure to be in your notes and/or textbook.
14 b. Let X be the discrete random variable integers from 1 to 50. You're told that sd(X) = 14.43 => Var(X) = (14.43)^2.
You're expected to know that Var(aX + b) = a^2 Var(X) => sd(aX + b) = |a| sd(X).
(i) a = 1/2, b = 0.
(ii) a = -1, b = 0.
(iii) a = 1, b = 99.
I have told you how to work it out. If you spent more than 5 minutes thinking about what I posted, then you might 'get how to work it out'.
|a| means the magnitude of a.
14 b. (i) The data is given by X/2 therefore sd = 1/2 sd(X) = 1/2 (14.43) = ....
(ii) The data is given by -X therefore sd = |-1| sd(X) = sd(X).
(iii) The data is given by X + 99 therefore sd = sd(X).