Question

Dr. Grey wanted to see if doctors prescribed different treatments for OCD for male patients compared to females. Please use the following frequency tables for the data collected by Dr. Grey.

Contingency table of Observed and Expected Frequencies of the different treatments (Drug vs. Cognitive Therapy) prescribed for patients with OCD.
Therapy Totals		Drug		Cognitive Therapy		Total
Gender of Patient		Observed	Expected	Observed	Expected
	Man	20		10		30
	Woman	15		15		30
	Total	35		25		60

What is your Conclusion - APA statistic?

A) χ2(1) = X.XX, p > .05

B) χ2(2) = X.XX, p < .05

C) χ2(2) = X.XX, p > .05

D) χ2(1) = X.XX, p < .05

Answer 1

Observed Frequencies
	Drug	Therapy	Total
Man	20	10	30
Woman	15	15	30
Total	35	25	60
Expected frequency of a cell = sum of row*sum of column / total sum
Expected Frequencies
	Drug	Therapy	Total
Man	17.5	12.5	30
Woman	17.5	12.5	30
Total	35	25	60

	(fo-fe)^2/fe
Man	0.357	0.5
Woman	0.357	0.5

Null and Alternative hypothesis:

Ho: factors are independent.

H1: factor are dependent.

Test statistic:

χ² = ∑ ((fo-fe)²/fe) = 1.7143

df = (r-1)(c-1) =1

Critical value:

χ²α = CHISQ.INV.RT(α, df) =3.841

p-value:

p-value = CHISQ.DIST.RT(χ², df) =0.1904

Decision:

p-value > 0.05, Do not reject the null hypothesis.

Answer A