Programming the statistical procedures from SAS

Steps in proving significance difference level

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Contributor
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Steps in proving significance difference level

I have a set of data of 52 weeks of actual output and demand. In order to prove their significant difference level, can anyone please show me the step in proving the sign. level?


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Super User
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Re: Steps in proving significance difference level

proc ttest for bi-variable normal distribution data.

proc npar1way for any distribution data.

Contributor
Posts: 34

Re: Steps in proving significance difference level

If I use chi square test to prove if there is any association between 2 variables? Is that ok?

Contributor
Posts: 34

Re: Steps in proving significance difference level

The chi-square statistic is 12.9102. The P-Value is 0.004835. The result is significant at p < 0.05.

Super User
Posts: 9,775

Re: Steps in proving significance difference level

That means they are associated .  But you should know chi-square test is for frequency analysis.   and If I don't get wrong your contingency table have lots of cells which freq less than 5 ,i.e. you should use Fisher exactly test.

Contributor
Posts: 34

Re: Steps in proving significance difference level

thanks for correcting me. I wil use the approach u mentioned and give you the answer asap... thanks for the guide~

Super User
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Re: Steps in proving significance difference level

You should know what goal you are trying to retrieve . after that , choose the right statistical method .

Contributor
Posts: 34

Re: Steps in proving significance difference level

for the fisher exact test, the test is only for 2x2 table?

Super User
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Re: Steps in proving significance difference level

no. you just need EXACT fisher statement to require this test.

Contributor
Posts: 34

Re: Steps in proving significance difference level

The results of an exact contingency table test performed at 19:07 on 8-NOV-2014

data: contingency table  A      B      C      D  1     10     19     17      6     52 2      1     16     18     17     52  11     35     35     23    104    expected: contingency table  A          B          C          D  1    5.50       17.5       17.5       11.5 2    5.50       17.5       17.5       11.5 

You have no "small" cells in the expected table...Use X2!

The given table has probability 1.3E-05
The sum of the probabilities of "unusual" tables, p = 0.004

Contributor
Posts: 34

Re: Steps in proving significance difference level

The results of an exact contingency table test performed at 19:07 on 8-NOV-2014

data: contingency table A B C D 1 10 19 17 6 52

2 1 16 18 17 52

11 35 35 23 104

expected: contingency table A B C D

1 5.50 17.5 17.5 11.5

2 5.50 17.5 17.5 11.5

You have no "small" cells in the expected table...Use X2!

The given table has probability 1.3E-05
The sum of the probabilities of "unusual" tables, p = 0.004

Super User
Posts: 9,775

Re: Steps in proving significance difference level

Curious. Is your contingency table one-way or two-way ?

Contributor
Posts: 34

Re: Steps in proving significance difference level

http://www.quantitativeskills.com/sisa/dataprocs/table2xn.php?ts=52&inp=i m using this to help in my calculation...

btw, can I use mann-whitney test in proving the significant different?

Super User
Posts: 9,775

Re: Steps in proving significance difference level

You misunderstand the contingency . You should firstly know what is row variable,what is column variable.

follow your mind, WEEK is row variable?

about mann-whitney test, if I am right it is almost like what I suggest proc npar1way + wilcoxon before .

Contributor
Posts: 34

Re: Steps in proving significance difference level

I had some difficulty in surfing internet now to get sufficient info on 7understanding the contingency.... can u kindly explain to me how to differentiate the row n column variable in this case ?

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