Autofill Questions

[Adam Louis]

Hello, I'm a casual Excel user of a few years, and I've recently come
across some issues. I would appreciate any insights you might have on
the subjects:

1) I wish to autofill a column to caluclate a cumulative product
percentage in such a way that the dataset can be expanded to any
length, so that:

Interval Percentage CumPer
1 .85 .85
4 .75 .64
10 .5 .32

This can be done:

Interval Percentage CumPer
1 .85 =B2
4 .75 =B3*C2
10 .5 =B4*C3

or

Interval Percentage CumPer
1 .85 =Product(B2:B2)
4 .75 =Product(B2:B3)
10 .5 =Product(B2:B4)

In the former method, I've tried C1=B1*C0, highlighting the column
(ie, click 'C', not individual cells) and filling down, with the
intention of manually refilling the first 2 rows with 'CumPer' and
'=B2'. This does not work. Is there any way to specify fill down for
the whole column, from something other than the row 1 source for that
column?

In the latter method, is there a way to make the B2 reference
constant, but the end parameter increment normally?

2) In trying to use this data to generate a step chart, I need it to
end up:

X Y
0 1
1 1
1 0.85
4 0.85
4 0.64
10 0.64
10 0.32

for an XY-scatter.

I've tried:

X
=0
=A1
=A1

where I've tried highlighting both of the '=A1' cells and dragging the
fill box down, and it does double up value, but it increments by 2:

X
=0
=A1
=A1
=A4
=A4
=A6
=A6

Is there any way to do this correctly?

Thank you for your assistance,

Adam Louis

 

[JE McGimpsey]

one way:

C2: =PRODUCT($B$2:B2)