Calculate the probability to reach at certain point......

[edneco]

Hello everyone..... I donīt know if this is the right place (if not Iīm sorry).......

I want to know if itīs possible to calculate the probability that a certain range of values, reach to a certain point.....

The range is this (example):

4
3
9
7
14
22
15
20
42
46
39
44
69
71
56
64
98
78
96
100
112
143
124
128
213
223
150
242
363
307
299
389
636
541
488
489


What I want to know is if this tendency will reach to 1000. Or how many steps more will be need to reach 1000.

Like I said, and donīt know if this is in the right place, but if you put this values in a graphic you will see that the tendency is growing. I assume that this tendency will reach to 1000. But will be in the next 10 steps or in the next 30.


I hope you understand this problem and could help me on this.........

[MrShorty]

Interesting challenge. I would first suggest that it is a math problem before an Excel problem.

Easiest approach might be to correlate the entire data set to an exponential curve (y=AB^x). This can be done using the LOGEST() function in Excel (http://office.microsoft.com/en-us/ex...in=HA010277524). Once you have the coefficients A and B, then you can use algebra to solve for x when y=1000.

Another approach might be to extract the "maxima" from the data set, and perform a similar analysis. The real difficulty here is how to identify and extract the "maxima" into their own table so you can use the LOGEST() function to regress that curve.

[edneco]

MrShortly thank for your rapid response..... I have already done the LOGEST() and I have already the coefficients A and B.

But now how can I solve the algebra problem??? Is there a Function for that???

Another thing is, but itīs for later, the data is given from web and I want to copy paste the values in a way like the ones that I put here (top down)..... So the range that I put in the LOGEST() function is not estatic. The range is always growing. So this function might not work for what I want. Maybe with some VBA code.

But first I need to figure how this function works, so I can put the problem to the VBA gurus.......

[MrShorty]

But now how can I solve the algebra problem??? Is there a Function for that???

Excel does not really do algebra. If you wanted, you can use the Goal Seek/Solver utilities to "solve" the equation, but the algebra in this case is so simple that I don't know why you would want to bother with that kind of solution (especially if this is headed into VBA).

Here's your algebra lesson for today (http://www.purplemath.com/modules/solvexpo2.htm). Excel has the built in logarithm function =LOG() and =LN(). VBA only has the natural log Log() function.