Trendline Equation
Is there a way to insert the equation of my trendline into calculations in my
worksheet. The rate is always changing each passing day due to more collected data... I wish to give a daily projection on when the certain maximum is going to be reached, which is goign to always be changing because of the changing trendline. Can I make reference to a data sereis trendline ie. y=10e^5x x = hours is there a way i can calculate x for a set y? and if the trendline changes, then so does the value of x? |
Trendline Equation
See
http://www.stfx.ca/people/bliengme/E...&%20LOGEST.htm best wishes -- Bernard V Liengme www.stfx.ca/people/bliengme remove caps from email "bastien86" wrote in message ... Is there a way to insert the equation of my trendline into calculations in my worksheet. The rate is always changing each passing day due to more collected data... I wish to give a daily projection on when the certain maximum is going to be reached, which is goign to always be changing because of the changing trendline. Can I make reference to a data sereis trendline ie. y=10e^5x x = hours is there a way i can calculate x for a set y? and if the trendline changes, then so does the value of x? |
Trendline Equation
thats a good site, however I do not have an inital value. i can't get the
value of B in the equation y=Be^Ax to equal the B in the trendline. but i can get A with with the logest formula. Any tips on getting the value of B? "Bernard Liengme" wrote: See http://www.stfx.ca/people/bliengme/E...&%20LOGEST.htm best wishes -- Bernard V Liengme www.stfx.ca/people/bliengme remove caps from email "bastien86" wrote in message ... Is there a way to insert the equation of my trendline into calculations in my worksheet. The rate is always changing each passing day due to more collected data... I wish to give a daily projection on when the certain maximum is going to be reached, which is goign to always be changing because of the changing trendline. Can I make reference to a data sereis trendline ie. y=10e^5x x = hours is there a way i can calculate x for a set y? and if the trendline changes, then so does the value of x? |
Trendline Equation
bastien86 -
For a solution using worksheet functions, to get the coefficients for Excel's exponential trendline function with form y = c*EXP(b*x), c = EXP(INTERCEPT(LN(yrange),xrange)) b = SLOPE(LN(yrange),xrange) For a specific yvalue, the corresponding x on the fitted curve is x = (LN(yvalue)-LN(c))/b So, if you put the formulas for c and b in worksheet cells, and if the formula for x has cell references to those cells and to a cell where you specify a yvalue, then c and b and x will update dynamically when you respecify the yrange or xrange. - Mike www.mikemiddleton.com "bastien86" wrote in message ... Is there a way to insert the equation of my trendline into calculations in my worksheet. The rate is always changing each passing day due to more collected data... I wish to give a daily projection on when the certain maximum is going to be reached, which is goign to always be changing because of the changing trendline. Can I make reference to a data sereis trendline ie. y=10e^5x x = hours is there a way i can calculate x for a set y? and if the trendline changes, then so does the value of x? |
Trendline Equation
My graph is displaying source data ='E3 Live '!$AK$1037:$AK$2168 and the
trendlines equation is y=.6954e^(-0.0001x). In my excel the formula "=EXP(INTERCEPT(LN(AK1037:AK2168),A1037:A2168) )" result in 0.802566202, shouldn't it result in 0.6954??? "Mike Middleton" wrote: bastien86 - For a solution using worksheet functions, to get the coefficients for Excel's exponential trendline function with form y = c*EXP(b*x), c = EXP(INTERCEPT(LN(yrange),xrange)) b = SLOPE(LN(yrange),xrange) For a specific yvalue, the corresponding x on the fitted curve is x = (LN(yvalue)-LN(c))/b So, if you put the formulas for c and b in worksheet cells, and if the formula for x has cell references to those cells and to a cell where you specify a yvalue, then c and b and x will update dynamically when you respecify the yrange or xrange. - Mike www.mikemiddleton.com "bastien86" wrote in message ... Is there a way to insert the equation of my trendline into calculations in my worksheet. The rate is always changing each passing day due to more collected data... I wish to give a daily projection on when the certain maximum is going to be reached, which is goign to always be changing because of the changing trendline. Can I make reference to a data sereis trendline ie. y=10e^5x x = hours is there a way i can calculate x for a set y? and if the trendline changes, then so does the value of x? |
Trendline Equation
bastien86 -
I do not have your worksheet data or your chart. But here is a possible explanation: If you are using an Excel XY (Scatter) chart type, then both the chart axes and the trendline will use the numerical values of the data ranges. If you are using an Excel Line chart type, then the x values are only being used as labels for the horizontal axis and the trendline is using 1,2,3,... as the x values. Use an XY (Scatter) chart type. - Mike www.mikemiddleton.com "bastien86" wrote in message ... My graph is displaying source data ='E3 Live '!$AK$1037:$AK$2168 and the trendlines equation is y=.6954e^(-0.0001x). In my excel the formula "=EXP(INTERCEPT(LN(AK1037:AK2168),A1037:A2168) )" result in 0.802566202, shouldn't it result in 0.6954??? "Mike Middleton" wrote: bastien86 - For a solution using worksheet functions, to get the coefficients for Excel's exponential trendline function with form y = c*EXP(b*x), c = EXP(INTERCEPT(LN(yrange),xrange)) b = SLOPE(LN(yrange),xrange) For a specific yvalue, the corresponding x on the fitted curve is x = (LN(yvalue)-LN(c))/b So, if you put the formulas for c and b in worksheet cells, and if the formula for x has cell references to those cells and to a cell where you specify a yvalue, then c and b and x will update dynamically when you respecify the yrange or xrange. - Mike www.mikemiddleton.com "bastien86" wrote in message ... Is there a way to insert the equation of my trendline into calculations in my worksheet. The rate is always changing each passing day due to more collected data... I wish to give a daily projection on when the certain maximum is going to be reached, which is goign to always be changing because of the changing trendline. Can I make reference to a data sereis trendline ie. y=10e^5x x = hours is there a way i can calculate x for a set y? and if the trendline changes, then so does the value of x? |
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