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Posted 03-23-2016 03:57 PM
(2253 views)

Hi Everyone,

I am trying to get the 95% confidence interval for a disease severity progression data set in SAS 9.4. The data have been log transformed and are not normal (certain weeks have a lot of 0 values). Sometimes the confidence limit output contains "." rather than numbers. In the year 2 output it seems that this only happens when the disease severy mean in 0 (see year 2 below), but in the year 1 data it happens for weeks when the disease severity mean is 0.3010 or 0 (see year 1 below). My question is: what does the "." mean? Why is a "." returned even when the mean is not 0?

Thank you

Sherri 🙂

This is the coding for year 2:

Title2 "Confidence Interval";

proc means data= first maxdec=4 alpha=0.05 clm mean;

class trt;

var jul23 jul31 aug6 aug13 aug20 aug27 sep3 sep10 sep17;

run;

and this is part of the output:

Coding for year 1

Title2 "Confidence Interval";

proc means data= first maxdec=4 alpha=0.05 clm mean;

class trt;

var aug21 aug30 sep14 sep24 oct11;

run;

Output for year 1:

8 REPLIES 8

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Here is data for trt 7 of year 1

block trt aug21 aug30 sep14 sep24 oct11; 1 7 0 0 0.2 0.5 1 2 7 0 0 0 0.6 1 3 7 0 0.1 0 0.9 1 4 7 0 0 0 0.5 1 ;

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Add Standard Deviation to the chart please and repost.

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Please see orginal message for update chart.

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Do you see the issue? 🙂

All results with missing CI have a standard deviation of 0 - implying that the values are all that single value.

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As Reeza pointed out . You can not calculated CI when it is at the highest level (nway), there is only one obs for that.
Specify WAYS statement.

proc means data= first maxdec=4 alpha=0.05 clm mean; class trt; ways 1 ; var jul23 jul31 aug6 aug13 aug20 aug27 sep3 sep10 sep17; run;

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