Best fit line

Question

regarding a graph made from spreadsheet data...
how do i make a best fit line to a set of points?
also, is there a way to find the slope and intercept of this line?
Thank you!

Answer 1

Hello
The named functions are not available in AppleWorks.
One way to mimic them is to use AppleScripts .
Here is an old one which calculate the slope.
--{SCRIPT}
tell application "AppleWorks 6"
activate
tell front document
set laSelection to get object specifier of the selection
set debutCible to name of first cell of laSelection
-- nom de la première cellule cible
-- • name of first dest cell
set premColonne to item 1 of (index of first column of laSelection) as list
set premRangee to item 1 of (index of first row of laSelection) as list
set dernColonne to item 1 of (index of last column of laSelection) as list
set dernRangee to item 1 of (index of last row of laSelection) as list
set nb_Rangees to dernRangee - premRangee + 1
if not (dernColonne - premColonne) = 1 then error 8088
set cell11 to name of row premRangee of column premColonne
set cell12 to name of row dernRangee of column premColonne
set cell21 to name of row premRangee of column dernColonne
set cell22 to name of row dernRangee of column dernColonne
set vX to get select (cells cell11 thru cell12)
set the clipboard to vX
set vY to get select (cells cell21 thru cell22)
set nb to count of vX
set {X, Y, XY, x2} to {0, 0, 0, 0}
repeat with i from 1 to nb
set xi to vX's item i
set yi to vY's item i
set X to X + xi
set Y to Y + yi
set XY to XY + (xi * yi)
set x2 to x2 + (xi * xi)
end repeat
set slope to (XY - (X * Y) / nb) / (x2 - (X * X) / nb)
select menu item 4 of menu 3 (* copier *)
set slope to my calcule(nb_Rangees)
display dialog "" & slope
end tell
end tell
on calcule(nb_)
tell application "AppleWorks 6"
activate
set AWversion to (version as text)
select menu item 2 of menu item 1 of menu 2 (* Nouveau tableur
• New spreadsheet *)
tell front document
select cell "A1"
select menu item 5 of menu 3 (* Colle • Paste *)
set formula of cell "C1" to "=A1*B1"
set formula of cell "D1" to "=A1^2"
select cell ("C1..D" & nb_)
select menu item 3 of menu 5 (* Recopier vers le bas
• Fill down *)
if AWversion starts with "FU1-" then
set formula of cell "E1" to "=(SOMME(C1..C" & nb_ & ")-SOMME(A1..A" & nb_ & ")*SOMME(B1..B" & nb_ & ")/NOMBRE(A1..A" & nb_ & "))/(SOMME(D1..D" & nb_ & ")-SOMME(A1..A" & nb_ & ")^2/NOMBRE(A1..A" & nb_ & "))"
else
set formula of cell "E1" to "=(SUM(C1..C" & nb_ & ")-SUM(A1..A" & nb_ & ")*SUM(B1..B" & nb_ & ")/count(A1..A" & nb_ & "))/(SUM(D1..D" & nb_ & ")-SUM(A1..A" & nb_ & ")^2/count(A1..A" & nb_ & "))"
end if
set slope_ to cell "E1"
end tell
close document 1 without saving
end tell
return {slope_}
end calcule
--{/SCRIPT}
Yvan KOENIG (from FRANCE mercredi 1 août 2007 06:51:46)
edit:
When I edit my message, the script appears but when I look in the forum it doesn't appear.
It appears that it is a recent "feature" of this forum;
I made a last attempt.
If it doesn't work, you may send a mail to
koenig then a dot then yvan then an @ then tele2 then a dot then fr
I will send you the script as a mail attachment.
Yvan KOENIG (from FRANCE mercredi 1 août 2007 07:07:17)
Message was edited by: KOENIG Yvan