Chi-Square

1
Chi-Square

• Test of Homogeniety

2
The following shows the results of 200 test
scores. Are the test scores normally distributed?
Score Freq
50 - 59 19  
59 - 68 61  
68 - 77 82  
77 - 86 34  
86 - 95 4  
3
Are your nuts evenly distributed?
nut observed
Bazil 112
Cashew 183
Almonds 207
Hazelnut 71
Peanut 446
4
Contingency Table

• Listed in terms of Rows X Columns
• Df (Rows -1) (Columns 1)
• Expected Value

5
Test for Homogeniety

• Test to see if proportions are the same

6
Test of Homogeniety

• State the hypotheses
• Assumptions
• Name of Test
• Compute expected values
• Find test statistic
• Find p-value
• Make Decision
• State Conclusion

7
An advertising firm has decided to ask 92
customers at each of three local shopping malls
if they are willing to take part in a market
research survey. At a 1 significance level, can
it be concluded that the proportions of those who
are willing to participate are equal?
Mall A Mall B Mall C
Will Participate 52 45 36
Will Not Participate 40 47 56
8
Survey of 300 1st time fathers to see if there
were in the delivery room when their child was
born. Are the proportions of those in the
delivery room the same at three local hospitals?
Hospital A Hospital B Hospital C
Present 66 60 56
Not Present 9 15 19
9
Lets check our eye dominance! Is it the same
for boys girls?
10
Homework

• Worksheet