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3.2 Finding Probabilities for Normal Distributions

3.2 Finding Probabilities for Normal Distributions

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Question 50

An automated sensor records temperature readings from a process that follows a normal distribution. Initially, the process is set with a mean of 55∘C55^{\circ}\text{C}55∘C and a standard deviation of 4.0∘C4.0^{\circ}\text{C}4.0∘C.

a.

Find the probability that a randomly recorded temperature reading is greater than 62∘C62^{\circ}\text{C}62∘C.

[3]
b.

The operator changes the mean to μ\muμ but maintains the standard deviation at 4.0∘C4.0^{\circ}\text{C}4.0∘C. The sensor then records 2 independent temperature readings.

The probability that both of these readings are less than 48∘C48^{\circ}\text{C}48∘C is 0.090.090.09.

Find the value of μ\muμ, giving your answer to 1 decimal place.

[4]
c.

The calibration is adjusted again so that the mean is 121212 and the standard deviation is 151515.

The sensor then records 4 independent readings from this distribution.

Find the probability that at least one of these readings is negative.

[4]
Markscheme

3.2 Finding Probabilities for Normal Distributions Questions

  1. A Level
  2. /Maths
  3. /3.2 Finding Probabilities for Normal Distributions

80 exam-style questions on Edexcel A Level Maths 3.2 Finding Probabilities for Normal Distributions. Each one has a worked solution and a mark scheme showing where the marks go.

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