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PostPosted: Sat Aug 13, 2011 6:41 pm 
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Joined: Fri Aug 12, 2011 10:06 pm
Posts: 4
Hi,

I'm new to the forum and I was wondering if someone can help me out. I'm not sure if this question is under the correct forum topic - my apologies for that!

I have been using excel all this while for basic frequencies and descriptives calculations. I'm trying to transition to SPSS and I was comparing the numbers for based on the excel calculation and SPSS output.

All the numbers match, except for Confidence Intervals - I'm getting a difference of 0.04 in the output. Everything is the same - mean, standard deviation and the sample size but, Lower and Upper bounds are off by 0.04.

Does anyone know why there would be a difference in both the calculations? Is there any way to correct that?

Thanks!
NKT

*Just realized that this was posted under the wrong forum topic.


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PostPosted: Mon Aug 29, 2011 2:23 pm 
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rounding?
or different confidence intervals (e.g. 1.96 vs. 1.98)?


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PostPosted: Mon Aug 29, 2011 4:52 pm 
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Different confidence interval.

Based on my research, I realized that Excel (everything later than 2007) uses Z-Test to calculate CI and SPSS only has the option for a T-Test for means and hence, the difference in confidence intervals.

Would you by any chance happen to know the syntax for a Z-Test?


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PostPosted: Tue Aug 30, 2011 8:17 am 
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I assume you mean: a variable with z-scores? or what do you mean?

you can write that yourself fairly easily based on the formula.
Use the aggregate function to create a variable with mean and sd.
If you can't get it to work come back


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