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vadiva vadiva
wrote...
Posts: 18
Rep: 4 0
9 years ago Edited: 9 years ago, bio_man
5.    Although the phenomenon is not well understood, it appears that people born during the winter months are more likely to develop schizophrenia than people born at other times. The following hypothetical data represent a sample of 50 individuals diagnosed with schizophrenia and a sample of 100 people with no psychotic diagnosis. Each individual is also certified according to season in which he or she was born. Do the data indicate a significant relationship between schizophrenia and the season of birth? Test at the 0.05 level of significance.

                           Season of Birth                                          

         Summer         Fall         Winter       Spring      total         
No disorder      26         24         22         28               100
 
Schizophrenia      9         11         18         12               50
 
total           35         35         40         40
 
 
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bio_manbio_man
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9 years ago
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wrote...
9 years ago
Of course you will have decimals. That is not an issue, just go about the computation as normal.

Just sum ((o-e)^2/e) and use that test-stat to find the p-value.


Expected:

....DISORDER................. .....SEASO...
.........................Summ er...........
.......no..............23.333 33...........
.......yes............11.6666 7........1...


Thus, sum the (observed - expected )^ 2 / expected to get the test stat

(26-23.333333)^2 / 23.33333 + (24-23.33333)^2 / 23.333333 +........ = 3.621428572 (approximately)

The degrees of freedom = (r-1)(c-1) = (2-1)(4-1) = 3 (there are 2 disorder options and 4 seasons)

Then go to a chi-square table and try to find the 3.62 value for 3 degrees of freedom

The test stat is larger than the p-value for the Chi-Square of .25. This means it is NOT significant at the .05 level. (p-value = .3053).

You can also do this in your TI-83 or higher calculator.

Just enter the observed into a 2x4 MATRIX A
Just enter the expected into a 2x4 MATRIX B

Then STAT, TESTS, scroll down to chi-Square(option C) and hit enter 3 times.

Should give you the exact stuff I did.
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But when you love a flower, you water it daily.
The one who understands this, understands life.

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vadiva Author
wrote...
9 years ago
Of course you will have decimals. That is not an issue, just go about the computation as normal.

Just sum ((o-e)^2/e) and use that test-stat to find the p-value.


Expected:

....DISORDER................. .....SEASO...
.........................Summ er...........
.......no..............23.333 33...........
.......yes............11.6666 7........1...


Thus, sum the (observed - expected )^ 2 / expected to get the test stat

(26-23.333333)^2 / 23.33333 + (24-23.33333)^2 / 23.333333 +........ = 3.621428572 (approximately)

The degrees of freedom = (r-1)(c-1) = (2-1)(4-1) = 3 (there are 2 disorder options and 4 seasons)

Then go to a chi-square table and try to find the 3.62 value for 3 degrees of freedom

The test stat is larger than the p-value for the Chi-Square of .25. This means it is NOT significant at the .05 level. (p-value = .3053).

You can also do this in your TI-83 or higher calculator.

Just enter the observed into a 2x4 MATRIX A
Just enter the expected into a 2x4 MATRIX B

Then STAT, TESTS, scroll down to chi-Square(option C) and hit enter 3 times.

Should give you the exact stuff I did.


Thank so much for your help .. the SPSS program I was using is on my desktop that crashed on me and I have two weeks left to go.
Post Merge: 9 years ago

Hope this helps...

I also corrected the title of the thread for you so that it's in the correct format of a question.
Thank you so much (so I am to basically post the first question in the title) I am starting to get it now. I am just panicked because my computer is down and I have two weeks left.
wrote...
9 years ago
Thank you for answering this question
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