Edexcel S2 january 2011 exam answers review
A disease occurs in 3% of a population. State any assumptions that are required to model the number of people with the disease in a random sample of size n as a binomial distribution.(2)...
Monthly Archive: July 2014
Edexcel FP3 January 2011 exam answers review
Express 2/(2r + 1)(2r + 3) in partial fractions.(2) Using your answer to (a), find, in terms of n, [IMAGE] Give your answer as a single fraction in its simplest form. (3) ANSWER z...
Edexcel S2 June 2013 exam answers review
A bag contains a large number of 1p, 2p and 5p coins. 50% are 1p coins 20% are 2p coins 30% are 5p coins A random sample of 3 coins is chosen from the...
Edexcel S2 january 2012 exam answers review
The time in minutes that Elaine takes to checkout at her local supermarket follows a continuous uniform distribution defined over the interval [3, 9]. Find Elaine’s expected checkout time,(1) the variance of the time...
Edexcel C4 June 2011 exam answers review
9x²/(x – 1)²(2x + 1) = A/(x – 1) + B/(x – 1)² + C/(2x + 1) Find the values of the constants A, B and C. (4) ANSWER f(x) = 1/√(9 + 4x²)...
Edexcel C4 january 2011 exam answers review
Use integration to find the exact value of \(\int_{\frac{\pi}{2}}{0} \)xsin2x dx (6) ANSWER The current, I amps, in an electric circuit at time t seconds is given by I = 16 – 16(0.5)t, t≥0...
Edexcel S2 january 2013 exam answers review
Write down the conditions under which the Poisson distribution can be used as an approximation to the binomial distribution.(2) The probability of any one letter being delivered to the wrong house is 0.01 On...
Conditional probability
This article explores solving problems using conditional probability. An event B may depend on event A that has already occurred. Consider the following Venn diagram. [IMAGE] The event A has already happened, so we’re...
Edexcel C4 january 2012 exam answers review
The curve C has the equation 2x + 3y2 + 3×2 y = 4×2. The point P on the curve has coordinates (–1, 1). Find the gradient of the curve at P.(5) Hence find...