Some suggested changes to statistical functions in Sheets

[Jon Cooper]

Dear all

I have been checking the description of the Trend function which is in
statistical.xml. To make it clear to the user how to use this function,
may I suggest the following changes to statistical.xml

Replace the line:

<Text>The TREND() function calculates a sequence of values based on a
linear regression of known value pairs.</Text>


with:

<Text>The TREND() function calculates a sequence of Y-values based on a
linear regression of known X- and Y-value pairs. For the input
parameters, the user must firstly select a cell-range containing the Y-
values, followed by the cell-range of the corresponding X-values.
</Text><Text>The line of best fit may be extrapolated to a different X-
range, which is specified as the 3rd parameter. However, the input X-
range should be given again if no extrapolation is required.
</Text><Text>The regression line can be forced to intersect the origin
(X=0, Y=0) by setting the 4th parameter, allowOffset, to FALSE or 0.
Setting this parameter to TRUE or 1 (the default) allows the best-fit
line to intersect the vertical axis at a non-zero value of Y.
</Text><Text>Note that since the result of this function is a row of
calculated Y-values, plotting the data will be facilitated if the X- and
Y- values are also in rows, rather than columns.</Text>


And (because I find this very confusing) may I suggest replacing the
line:

<Syntax>TREND(knownY[;knownX[;newX[;allowOffset = TRUE]]])</Syntax>



with:

<Syntax>TREND(known Y-range; known X-range; new X-range;
allowOffset=TRUE/FALSE)</Syntax>


If you make those changes, it looks like the attached screenshot and I
think it will help the user to avoid crashing the program!!

--
Jon Cooper
jbcooper at fastmail.net
 
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