OCR S1 2011 June — Question 3

Exam BoardOCR
ModuleS1 (Statistics 1)
Year2011
SessionJune
TopicBinomial Distribution
TypeSum or combination of independent binomial values

3
  1. A random variable, \(X\), has the distribution \(\mathrm { B } ( 12,0.85 )\). Find
    (a) \(\mathrm { P } ( X > 10 )\),
    (b) \(\mathrm { P } ( X = 10 )\),
    (c) \(\operatorname { Var } ( X )\).
  2. A random variable, \(Y\), has the distribution \(\mathrm { B } \left( 2 , \frac { 1 } { 4 } \right)\). Two independent values of \(Y\) are found. Find the probability that the sum of these two values is 1 .