Binomial Test

Question 1

Binomial Test

Answer 1

• Simplest inf test; focuses on prob of frequencies occurring by chance rather than the hypothetical; uses CR & ML; stresses important of BASE RATE; IV property; questions whether what we observe is different from what we expect aka. from the base rate?

Question 2

BT (EG)

Answer 2

• IE. Is the frequency of females in PSY1205 significantly different to the frequency of males?

Question 3

BT 1

Answer 3

o 1. GET RANDOM SAMPLE
o 16; 13F, 3M
o Given the sample size, what is the prob of this dif being by chance?

Question 4

BT 2

Answer 4

o	2. IDENTIFY VALUES OF EACH VARIABLE
o	Prob(X)=N!/X!(N-X)!p^xq^(N-X)
o	Prob=XFEM in N students assuming = sex ratio
	13F in 16 students
o	COMBO=dif ways of getting FEM from sample
	Dif ways of getting 13F in 16 students
o	Q=not 	FEM
	Assume 0.5
o	P=FEM
	Assume 0.5
o	Prob(X)=16!/13!(16-13)!0.5^13x0.5^3
o	=(16x15x14/3x2x1)0.5^13x0.5^3
o	P=0.008

Question 5

BT 3

Answer 5

o 3. CHANGE P/Q

o 7:3 (F:M) base rate

Question 6

BT 4

Answer 6

o 4. IDENTIFY VALUES FOR VARIABLES
o …P=.146>.05
o NOT STATSIG; accept H0; sex ratio no dif to pop