What is a p-value?

Foundations of Inference in R

Jo Hardin

Instructor

Understanding the null distribution

Observed data

	Promoted	Not promoted
Male	21	3
Female	14	10

ch2_4_v3.004.png

Observed data

	Promoted	Not promoted
Male	21	3
Female	14	10

ch2_4_v3.005.png

Observed data

	Promoted	Not promoted
Male	21	3
Female	14	10

ch2_4_v3.006.png

Observed data

	Promoted	Not promoted
Male	21	3
Female	14	10

ch2_4_v3.007.png

Observed data

	Promoted	Not promoted
Male	21	3
Female	14	10

ch2_4_v3.008.png

Observed data

	Promoted	Not promoted
Male	21	3
Female	14	10

ch2_4_v3.009.png

Probability of observing data as or more extreme than what we actually got given that the null hypothesis is true

Probability of a observing a difference of 0.2917 or greater when promotion rates do not vary across gender = 0.03

Foundations of Inference in R