Interpolation Problem
 

Let's say I have 2 values: one at F1 and the other at F8.
By using linear interpolation I can solve for F2, F3, F4, F5, F6 and F7
(the two other values that are needed for the interpolation are not
relevant for my problem).

Problem:
The two values that I have are not always in F1 and F8.
They now can be at F2 and F7.

Question:
How can I apply the interpolation without knowing where exactly my two
values appear? I do know for sure that I have two values and that there
are cells in between those two values that are needed to take
interpolated values...

I hope I am clear.

Thanks.

Interpolation Problem
 

I guess I was not clear enough, so I'll try again.
This is what I have now:
B C
2 12/19/2006 0.999706
3 12/20/2006
4 12/21/2006
5 12/22/2006
6 12/23/2006
7 12/24/2006
8 12/25/2006 0.998675

I can solve for C3, C4 etc.

But when I open my excel tomorrow, for example, the number in C2 might
be now in C3 and the one in C8 might go to C7. In this case I will
still want to solve for anything that is between a number above and
below...

Thanks.


Tom Ogilvy wrote:
You need 4 values. Two "x" values and two "y" values.

then you just solve for the equation of the line and substitute in the new
value of x for which you want a estimated value of Y.

In your example, 1 and 8 I assume represent the x values.

If the values you have are 2 and 7, then use those as your x values and
solve for the equation. Once you have the equation, it doesn't make any
difference where the new x value is in relation to the known values (from a
mechanical standpoint - obviously building an extimate of a value far away
from the known values is usually ill advised.

Use the SLOPE:
SLOPE(known_y's,known_x's)

Known_y's is an array or cell range of numeric dependent data points.

Known_x's is the set of independent data points.


and INTERCEPT formulas

INTERCEPT(known_y's,known_x's)

Known_y's is the dependent set of observations or data.

Known_x's is the independent set of observations or data.

to build your equation

See excel help for details.

--
Regards,
Tom Ogilvy


"amirstal" wrote:

Let's say I have 2 values: one at F1 and the other at F8.
By using linear interpolation I can solve for F2, F3, F4, F5, F6 and F7
(the two other values that are needed for the interpolation are not
relevant for my problem).

Problem:
The two values that I have are not always in F1 and F8.
They now can be at F2 and F7.

Question:
How can I apply the interpolation without knowing where exactly my two
values appear? I do know for sure that I have two values and that there
are cells in between those two values that are needed to take
interpolated values...

I hope I am clear.

Thanks.

Interpolation Problem
 

Perhaps you can use:

=MAX(C2:C8)

and

=MIN(C2:C8)

HTH,
Bernie
MS Excel MVP


"amirstal" wrote in message
ps.com...
I guess I was not clear enough, so I'll try again.
This is what I have now:
B C
2 12/19/2006 0.999706
3 12/20/2006
4 12/21/2006
5 12/22/2006
6 12/23/2006
7 12/24/2006
8 12/25/2006 0.998675

I can solve for C3, C4 etc.

But when I open my excel tomorrow, for example, the number in C2 might
be now in C3 and the one in C8 might go to C7. In this case I will
still want to solve for anything that is between a number above and
below...

Thanks.


Tom Ogilvy wrote:
You need 4 values. Two "x" values and two "y" values.

then you just solve for the equation of the line and substitute in the new
value of x for which you want a estimated value of Y.

In your example, 1 and 8 I assume represent the x values.

If the values you have are 2 and 7, then use those as your x values and
solve for the equation. Once you have the equation, it doesn't make any
difference where the new x value is in relation to the known values (from a
mechanical standpoint - obviously building an extimate of a value far away
from the known values is usually ill advised.

Use the SLOPE:
SLOPE(known_y's,known_x's)

Known_y's is an array or cell range of numeric dependent data points.

Known_x's is the set of independent data points.


and INTERCEPT formulas

INTERCEPT(known_y's,known_x's)

Known_y's is the dependent set of observations or data.

Known_x's is the independent set of observations or data.

to build your equation

See excel help for details.

--
Regards,
Tom Ogilvy


"amirstal" wrote:

Let's say I have 2 values: one at F1 and the other at F8.
By using linear interpolation I can solve for F2, F3, F4, F5, F6 and F7
(the two other values that are needed for the interpolation are not
relevant for my problem).

Problem:
The two values that I have are not always in F1 and F8.
They now can be at F2 and F7.

Question:
How can I apply the interpolation without knowing where exactly my two
values appear? I do know for sure that I have two values and that there
are cells in between those two values that are needed to take
interpolated values...

I hope I am clear.

Thanks.