VG2
statistikk
Quiz
What is the normal distribution?
The normal distribution is the most famous probability distribution in statistics — the characteristic bell curve that describes everything from height and weight to exam results.
What is the normal distribution?
The normal distribution is symmetric about the mean and has a bell curve shape. It is described by:
- μ (mu) = the mean
- σ (sigma) = the standard deviation
The 68-95-99.7 rule
68% of data lies within ±1σ of μ
95% of data lies within ±2σ of μ
99.7% of data lies within ±3σ of μ
95% of data lies within ±2σ of μ
99.7% of data lies within ±3σ of μ
Z-score
z = (x - μ) / σ
A man 194 cm tall: z = (194-180)/7 = 2 — two standard deviations above average.
It is not knowledge, but the act of learning which grants the greatest enjoyment. When I have clarified and exhausted a subject, then I turn away from it.
— Carl Friedrich Gauss (1777–1855)
🧠 Test yourself
Question 1 of 3
What percentage of data lies within ±2σ from the mean?