Question

Imagine that we took a large sample of respondents and measured their education. The sample mean =16 years and the sample standard variation = 1.5 : using that information,what is the 40th percentile of education. Show work.

Answer 1

Solution :

mean = = 16

standard deviation = = 1.5

Using standard normal table,

P(Z < z) = 40%

P(Z < z) = 0.40

P(Z < - 0.2533) = 0.40

z = - 0.25

Using z-score formula,

x = z * +

x = - 0.25 * 1.5 + 16

= 15.625

P₄₀ = 15.62