Chi Square Test
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 This topic has 5 replies, 5 voices, and was last updated 16 years, 2 months ago by Sanjay Kumar.

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May 7, 2004 at 7:28 pm #35477
Can you help, currently i am having great difficulty in understanding the Chi Square test, could somebody send me some examples of how to use a Chi Square test and also how to intepret the results.
Your help and assistance is very much appreciated, and thank you in anticipation.
0May 7, 2004 at 8:51 pm #99943Please find attached the failure rate for 5 vehicle lines vs cause for rejection.
I have been ask to complete a Chi Square test on this data, and i am very unsure about how to complete this.Cause for Rejection
Vehicle Type
Split Tyre
Seat Bolt
Flat Tyre
Bolt in Tread
Damage / Worn
Damaged Rim
Damaged Wheel
Puncture
Damaged Side Wall
Scratched Wheel
Cut On Side Wall
TotalA
1
4
1
13
0
1
5
4
0
4
1
34B
0
0
0
0
2
0
3
3
0
3
0
11C
0
0
0
0
0
1
0
0
0
0
0
1D
0
0
0
12
0
0
1
10
3
0
0
26E
0
0
0
0
0
0
1
6
0
0
0
7Total
1
4
1
25
2
2
10
23
3
7
179
Could somebody send me some details of how to complete the test. i am looking for the following answers for
a) Do the vehicle types differ with regard to the proportions of failures within each category,
b) Does the distribution of rejects differ from vehicle o vehicle.
Regards
Rob
0May 10, 2004 at 6:46 am #99981
fernandoParticipant@fernando Include @fernando in your post and this person will
be notified via email.I suggest you this link:
http://faculty.vassar.edu/lowry/webtext.html
It’s been very useful to me to clarify some concepts. Every subject is explained starting from an example
You can also download the PDF version
Fernando0May 13, 2004 at 4:25 pm #100187Rob:
You have an interesting problem that you have been working on. I am surprised that you have not received a greater response.
Here are three comments that might stimulate additional thoughts.
1. It appears that the sample size is relatively small to draw strong conculsions. For example, for split trye chisquare = 4. With df=4, and chisquare = 9.488 at the 5% confidence level, there is no statistical difference between vechicle types. In other words, you can not reject the null hypothesis (Ho: cause A=B=C=D=E).
2. There is a real danger when statistics is applied to this problem. A simple statement to management that there is no statistical difference between the vechicle types for split trye could lead to a belief that there is no need to revisit this question with a large sample size
3. Chisquare = 47.76 for the totals — statistically significant. The data clearly shows that some vechile types are worse than others. In the case of vechicle type B and E, what did you do to determine if there is a statistical difference between these two vechicle types?
I would be interested in finding out more about your final analysis.0May 13, 2004 at 4:32 pm #100190A great way to set this up is to use a Pivot Table in Excel, then run the ChiSquare function. I’ll set it up and give it a try.
0July 16, 2004 at 10:52 am #103558
Sanjay KumarMember@SanjayKumar Include @SanjayKumar in your post and this person will
be notified via email.Dear ,
Please mail me that table if you can.
Regards,
Sanjay Verma0 
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