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### Averaging

Figure 3: Overlay of profiles before averaging

Figure 4: Median values with percentile error bars

You can average  data points over evenly spaced x intervals. Error bars  can show the standard deviation of the mean in both x and y or the error estimate of the mean. To average data, set the number of intervals you want. To stop averaging, reset the number of intervals to zero. If you have lots of clusters of points and you want only nearby points averaged, try choosing a very large number of intervals even though many intervals will have no points in them. The absence of an error bar means that only one point is in that interval. Symbol  groupings, if defined, are retained in the averaging process. You can fit averaged data.

A median  option is also available. Figure 3 is a graph of points representing several profiles and Figure 4 is a graph of the median profile where the error bars show where a specified percentage   of the points lie centered about the median.

```    <3=A;> Analysis: Average, Frequency, ... ? <AV>:      AV

<4> Number of intervals for averaging? <10>:          20

\* Options are:
1) Standard deviation of the data (sd) or
2) Error on the estimate of the mean (sd/sqrt(n))
3) Percentile error bars (medians, not means are shown)

<5> Error bar represents? <S>:                        PE
<6> Y percentile (error bar will show inner y%) <90>: 68
<7> X percentile (error bar will show inner x%) <100>: 0```

Figure 5: Frequency plot

Marilee Thompson
Fri Jul 11 17:05:56 EDT 1997