Exercise to produce a histogram of WAZ scores in Kenya East:

1. Open **keast4j.sav**

2. In the Data Editor menu,
click on *Graphs, Histogram*

3. Select **waz **from
the list of variables and place it in the *Variable *box using the arrow key

4. Click on the box marked *Display
normal curve* and click *OK*

**INTERPRETATION: **This histogram does
approximate a normal or Gaussian distribution, as expected for a z-score. A normal
distribution is expected because nutrition status is measured on a continuous scales,
where the majority (95%) of any population will lie within 2 SD of the mean, while
approximately 2.5% will be significantly above and 2.5% will be significantly below the
mean. When referring to nutrition status, the cut-off for z-score is usually within 5 SD
of the mean (in either direction) because any measurement beyond that would indicate that
an error was made in the data collection (a value this extreme is so unlikely that it is
not reliable). This histogram has been cleaned (all values above and below 5SD have
been eliminated) and shows a shift in the mean down the scale to -1.29 SD. This
would indicate that the average child under 5 years (for which the measurements were
taken) is at least mildly underweight in comparison with a normal population (and likely
the population has a malnutrition problem).