The random variable J has a Poisson distribution with mean 4. Find P(J>2)

P(J>2) = P(J=0)+P(J=1)     [split it up]

P(X=t)= (V^t)/t!*e^V       where V=4 in this case  [use the formula]

P(J>2) = 4^0/0!*e^4 + 4^1/1!*e^4

          =1/e^4 + 4/e^4  =  5e^-4  which is roughly  0.0916

NC

Related Maths A Level answers

All answers ▸

A curve passes through the point (4, 8) and satisfies the differential equation dy/dx = 1/ (2x + rootx) , Use a step-by-step method with a step length of 0.3 to estimate the value of y at x = 4.6 . Give your answer to four decimal places.


Find the derivation of (sinx)(e^2x)


(i) Prove sin(θ)/cos(θ) + cos(θ)/sin(θ) = 2cosec(2θ) , (ii) draw draph of y = 2cosec(2θ) for 0<θ< 360°, (iii) solve to 1 d.p. : sin(θ)/cos(θ) + cos(θ)/sin(θ) = 3.


How would I differentiate y=2(e^x)sin(5x) ?