finding angle of slope...

Discussion in 'Microsoft Excel Charting' started by Brad, Jun 21, 2006.

1. BradGuest

Using Chart, Add Trendline, then selecting Linear in Excel to chart a linear
regression line on a series creates a new line on my chart with either a
positively or negatively sloped regression line.

Is there any way, using this built-in Excel feature, to convert the result
into degrees so that I can then label the regression line in degrees, for
example, 45 degrees?

My thanks for any ideas. Brad

Brad, Jun 21, 2006

2. James SilvertonGuest

Brad wrote on Wed, 21 Jun 2006 15:52:26 -0500:

B> Is there any way, using this built-in Excel feature, to
B> convert the result into degrees so that I can then label the
B> regression line in degrees, for example, 45 degrees?

You could display the equation of the trend line where the
coefficient of X is the slope tho' I believe it would be more
accurate, in earlier versions of Excel, to use LINEST to get the
slope; slope:=INDEX(LINEST(known_y's,known_x's),1). Then all you
have to do is convert the slope, which is the tangent of an
angle, to the angle = DEGREES(ATAN(SLOPE)). See LINEST and other
worksheet functions in HELP.

James Silverton.

James Silverton, Jun 21, 2006

3. Bernard LiengmeGuest

The functions SLOPE and INTERCEPT give the m and c of y=mx+c, respectively
Suppose A1 and B1 have text such as X and Y, while A2:A10 have the x-values
and B2:B10 have the y-values
In D2, I entered =SLOPE(B2:B10,A2:A10) and get a slope value (in my example
it was 2)
Now this slope is the tangent of the line; so ATAN(D2) will tell me the
angle
But like most computer programs,Excel thinks of angles in radians (the only
'pure' measure to use)
If I want degrees I need to convert the result to degrees; let's do it all
in one cell with formula =DEGREES(ATAN(D2))
Or it I want to be very clever I could use a single cell with
=DEGREES(ATAN(SLOPE(B2:B10,A2:A10)))
The answer displays as 75.96376
If I want to see degrees, minuets an second I will visit Chip's site at
http://www.cpearson.com/excel/latlong.htm and re-learn how to do it (I
actually like decimal values)
best wishes

--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email

"Brad" <> wrote in message
news:%...
> Using Chart, Add Trendline, then selecting Linear in Excel to chart a
> linear regression line on a series creates a new line on my chart with
> either a positively or negatively sloped regression line.
>
> Is there any way, using this built-in Excel feature, to convert the result
> into degrees so that I can then label the regression line in degrees, for
> example, 45 degrees?
>
> My thanks for any ideas. Brad
>

Bernard Liengme, Jun 21, 2006

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