Question

A survey asks a group of students if they buy CDs or not. It also asks if the students own a smartphone or not. These values are recorded in the contingency table below. Which of the following tables correctly shows the expected values for the chi- square homogeneity test? (The observed values are above the expected values.) CDs No CDs Row Total 23 14 37 Smartphone No Smartphone Column Total 14 22 36 37 36 73 Select the correct answer below: О CDs 23 Smartphone 18.8 14 No Smartphone 18.2 Column Total 37 No CDs Row Total 14 37 18.2 22 36 17.8 36 73 O CDs No CDs Row Total 23 14 37 Smartphone 19.8 16.2 14 22 36 No Smartphone 20.2 15.8 Column Total 37 36 73

Answer 1

Solution:

Expected frequency table.

	CDs	No CDs	Row Total
Smartphone	$\frac{37*37}{73}=\frac{1369}{73}=18.8$	$\frac{37*36}{73}=\frac{1332}{73}=18.2$	37
No smartphone	$\frac{37*36}{73}=\frac{1332}{73}=18.2$	$\frac{36*36}{73}=\frac{1296}{73}=17.8$	36
Column Total	37	36	73

	CDs	No CDs	Row Total
Smartphone	23 18.8	14 18.2	37
No smartphone	14 18.2	22 17.8	36
Column Total	37	36	73

Option A is correct.