Question 6: Calculate the standard deviation of the difference between the two measurements of head circumference.
We can find the mean and standard deviation of the difference using Descriptive Statistics, Descriptives.
We get the following output:
| Descriptive Statistics | |||
|---|---|---|---|
| N | Mean | Std. Deviation | |
| difference | 300 | -.5033 | 12.78547 |
| Valid N (listwise) | 300 | ||
One decimal place should be enough here. Even that might be too much, as the first decimal place would be tenths of a milimetre. The standard deviation of differences between successive head circumference measurements = 12.8 mm.
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Last updated: 23 January, 2012.