Steps in proving significance difference level

[koksiang100]

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?

[Ksharp]

proc ttest for bi-variable normal distribution data.

proc npar1way for any distribution data.

[koksiang100]

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

[koksiang100]

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

[Ksharp]

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.

[koksiang100]

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

[Ksharp]

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

[koksiang100]

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

[Ksharp]

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

[koksiang100]

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

[koksiang100]

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

[Ksharp]

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

[koksiang100]

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?

[Ksharp]

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 .

[koksiang100]

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 ?