Mean WAZ score and Prevalence <-2 SD by Measles Immunization


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Exercise in Running the Mean Outcome scores:

1.  Open keast4j.sav

2.  Click on Statistics, Compare Means, Means and enter waz (weight for age z-score) and waprev (weight for age prevalence <-2 SD) in the  Dependent Variable list using the arrow key.

3.  Enter the variable hmeasyn (yes/no for measles immunization) into the Independent Variable box.

4.  Click on OK.

wpe1.jpg (13218 bytes)

INTERPRETATION: 

The outcome is shown so the mean WAZ score can be compared between the immunized and non-immunized group. There is a higher z-score (better nutritional status overall) for those children who have not been immunized (-0.916 compared to -1.429).  This corresponds to the outcome for prevalence, where the numbers should be multiplied by 100 to give the percentage.  There are only 22% under -2 SD for those not immunized, but 33% under -2 SD for those that did get immunized.  This could seem perplexing, since one would think that immunizing a child would have a protective, not a harmful effect.   Think about this for a bit.  Don't just believe what you see until you look further.

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