CAIE: A Level - Mathematics 9709 - Probability and Statistics 1
Normal Distribution / Finding Probability through Normal Distribution
KEYPOINTS:
Normal Distribution is written as X ~ N(μ, σ2)
Standard Normal Distribution has Mean 0 and Variance 1.
Standardised score z = \(\frac{x - \mu}{\sigma}\), where x is the raw score, μ is the mean and σ is the standard deviation.
Probability can be found from the Normal distribution table using z–score.
φ(z) = P(Z ≤ z), φ(-z) = 1 - φ(z)
Normal Distribution is continuous, symmetric and infinite in both directions and has a single peak at the centre.
95% of values lie within approximately 2 standard deviations of the mean.
99% of values lie within approximately 3 standard deviations of the mean.
Past Papers Topic Wise QuestionsA Level: Mathematics 9709 - Probability and Statistics 1Normal Distribution | Finding Probability through Normal Distribution
