Please help with average formula

[tonguencheek]

Let's say I have a column of data and I want to find the average based on the number of periods which can be manually inputted in cell A1.

The column of data starts in C1 and the formula will be entered in A2.

As an example, if the user enters "10" in A1, then it will average (a1:a10). If they enter 50 it would average (a1:a50) etc.

Any help would be great.

Also, how can you make it so that excel DOESN'T ignore blank cells when computing and average?

 

[xlmaniac]

Hi,
Assuming that your data range from A1:A16 as follows:-
<TABLE style="WIDTH: 48pt; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=0 width=64 border=0 x:str><COLGROUP><COL style="WIDTH: 48pt" width=64><TBODY><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 48pt; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" width=64 height=17 x:num>1</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>2</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>3</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>4</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>5</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>6</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>7</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>8</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>9</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>10</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>12</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>13</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>14</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>15</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD class=xl24 style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17 x:num>16</TD></TR></TBODY></TABLE>

And the input cell in B1.
Put the formula in B2=AVERAGE(OFFSET($A$1,0,0,B1,1))

 

[Scott Huish]

Assuming you want blank cells to count as zero:

=AVERAGE(IF(C1:INDEX(C:C,A1)="",,C1:INDEX(C:C,A1)))

Confirm with CTRL-SHIFT-ENTER rather than just Enter.

If you want it to ignore blank cells, then it is just:

=AVERAGE(C1:INDEX(C:C,A1))

 

[Aladin Akyurek]

Try...

A2:

=SUM(OFFSET($C$1,0,0,A1))/A1