Linear
Regression Explained
by Howard Arrington
A Linear Regression (LR) line is a trend line that is
drawn mathematically so that is represents the 'best fit'
for the data points it passes through. The formulas use the
least squares method to determine the line's placement.
This minimizes the distances between the data points and the
trend line.
The algebraic expression for a straight line is: y
= b * x + a where b is the slope of the
line and a is the y-intercept. The linear
regression formula calculate both the b and the
a values.
This chart shows a linear regression trend line in its 'best
fit' position.
One technique is to draw equally spaced
channel lines at a distance based on Standard Deviation.
The Linear Regression draw tool in Ensign Windows has a
multiplier parameter for the Standard Deviation offset. The
following example shows red channels lines drawn at 2 times
the Standard Deviation. Prices that stay outside of the
regression channel indicate a change in trend.
The next technique that is based on Linear
Regression trend lines, is to calculate a Linear Regression
line for every set of n bars, and determine the
price where the trend line intercepts the last bar in each
data set. Thus, one data point is determined for each bar
in the chart, and these data points are then connected to
create a Linear Regression curve, quite like a moving
average. The next chart illustrates several LR lines that
each span a set of 5 bars. The price where the LR line
intercepts the last bar in each set of 5 bars is marked with
a dot. These intercept points are then connected by the red
line to form a curve.
The study in Ensign Windows which is based
on the above technique is called Regression Channel. The
center line is calculated as illustrated in the prior
example. Then bands are added whose distance from the
regression center line is based on Standard Deviation.
The last technique discussed in this article
is to plot the Slope of each Linear Regression trend line
that is calculated for each set of n bars. In our
earlier example with several LR lines, each LR line has a
slope. Some have positive slopes wherein the lines are
ascending. Some have negative slopes wherein the lines are
descending. A change in the slope can be an early
indication that the trend is changing direction.
This example shows the Regression Channel,
with the Linear Regression Slope study plotted in green.
The Linear Regression Slope (LRS) is a plot
of the b values calculated for each set of n
bars. In the last 3 illustrations, n had a value
of 5. This small set size makes for a choppy channel and a
choppy LRS. The lead article in this newsletter is a better
example of how the LRS will look on a chart, and the set
size parameter will be more useable when in the neighborhood
of 10.
Ensign Windows users who would like to
investigate the Linear Regression Slope study would select
the Regression Channel from the study list, and check the
Plot Slope (LRS) check box on the study property form. The
LRS will be plotted instead of the Regression Channel.
Upper and Lower bands may be added to the plot.
Mail Bag:
'The addition of volume to the Tick charts has become an
invaluable tool. As I believe volume is often a leading
indicator of price, I use volume extensively to make
decisions. With the reduced ES e-mini volume of late, being
able to monitor volume on a tick chart with the Chaikin
indicator study had added a whole new dimension to trading
with tick charts. Additionally, the Volume bar features has
again added another dimension to viewing price action and,
along with contract volume on ticks, aids greatly in making
trading decisions.' -A. Gallo 06-28-2004
'Thank you for this product as well as your commitment to
traders and their success in the markets. The Statistics
page is one of many examples of this. What an amazing tool
at my fingertips! It has aided me in selling the high of
the day, on several occasions this year, as this was made
for months between 12:30 and 1:00 pm. This still occurs
from time to time but the market environment has changed
some. It has gotten more choppy and less trendy. My
trading style has changed to accommodate this and to take
advantage of the large overnight gaps that are occurring in
the grains markets. So most of my positions are now being
taken or exited near the close.' -J. Shea
06-19-2004
'Thanks for providing us with the very best charting
software available and with absolutely the best support.
Trading is a hard nut to crack..... Ensign Software gives me
the edge.' -B. Davis 06-16-2004
'Impressive support! Thanks you for the amazing
response. What you've implemented will go a long way to
making the trading strategy much easier for the client to
use. I'm sure she will be impressed by what you've done to
help out.' -I. Vanier 06-12-2004
'I have received your latest newsletter where you
mentioned Bradley siderograph and it seems to me that you
are interpreting it somewhat incorrectly. You wrote "It
denotes patterns, trends and the timing of swing tops and
bottoms." Consensus among financial astrologers is that
Bradley siderograph indicates only turning points within
about +/- 6 days and quite often they are inverted. I don't
know how familiar are you with astrology and with how BS is
calculated but it can not reliably predict the direction,
tops, bottoms etc. But those turning points are quite often
correct (if you are investing long term) even when sometimes
inverted. Actually, there were a number of different models
of the siderograph created in recent years and they were
tuned to different markets. But even as an astrologer I
have to say you will get more useful information just by
putting a moving average on the chart.' -A.
Klouda |