The lifetimes, in hours, of a particular type of light bulb are normally distributed with mean 2000 hours and standard deviation σ hours. The probability that a randomly chosen light bulb of this type has a lifetime of more than 1800 hours is 0.96. New technology has resulted in a new type of light bulb. It is found that on average one in five of these new light bulbs has a lifetime of more than 2500 hours.

A selection of 3 letters from the 8 letters of the word COLLIDER is made.

Last Saturday, Sarah recorded the colour and type of 160 cars in a car park. All the cars that were not red or silver...

The discrete random variable X has the following probability distribution. X|-2|0|1|3|4 P(X = x)|0.2|0.1|p|0.1|q

The variables x and y satisfy the equation yⁿ = Ax³, where n and A are constants. It is given that y = 2.58 when x = ...

The parametric equations of a curve are x = 2t + sin 2t, y = 1 – 2 cos 2t, for −½π < t < ½π.

The variables x and θ satisfy the differential equation x cos² θ (dx/dθ) = 2 tan θ + 1, for 0 ≤ θ < ½π and x > 0. It ...