Normal distributions (AQA GCSE Statistics): Flashcards
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What conditions must data meet for normal distribution?
What conditions must data meet for normal distribution?
Continuous, symmetrical, bell-shaped, with equal mean, median, mode.
What percentage of values lie within 1 standard deviation?
What percentage of values lie within 1 standard deviation?
68% of all values lie within ±1 standard deviation.
How to calculate standard deviation from data values?
How to calculate standard deviation from data values?
Find mean, then use: sqrt(sum((value - mean)^2)/n).
Find mean if 50% of heights are greater than 13.5cm.
Find mean if 50% of heights are greater than 13.5cm.
Mean (μ) = 13.5cm, as it's the median in normal distribution.
How to find P(X > 18) for μ=13.5, σ=1.5 using Z-scores?
How to find P(X > 18) for μ=13.5, σ=1.5 using Z-scores?
Calculate Z = (18-13.5)/1.5, then find P(Z > value).
What does the empirical rule state for 2σ?
What does the empirical rule state for 2σ?
95% of values lie within ±2 standard deviations.
How to visualize normal distribution in problems?
How to visualize normal distribution in problems?
Sketch the curve showing mean and 3 standard deviations.
What does 'greater than' mean in normal distribution?
What does 'greater than' mean in normal distribution?
It refers to the area to the right of the value on the curve.
Why is symmetry important in normal distributions?
Why is symmetry important in normal distributions?
It allows applying information from one side to the other.
What common mistake to avoid in calculations?
What common mistake to avoid in calculations?
Double-check arithmetic, especially in standard deviation steps.