calculating formula only on active rows

This site has been very helpful in my programming questions so far, but I couldn't find this one on a thread yet.

I have 3 columns of information, (A) study ID (B) effect size (C) inverse variance. The rows are pasted from other worksheets where other calculations are made. They are automatically pasted into the next empty row.

After all previous calculations have been made, I need to do some more on this page. I created the code below (well, I recorded it), but it is only for the first row. I can't just paste the formula to every row because then they will not appear as blank rows for the other macros. I want the code to automatically be calculated for every row that has numbers. Thanks so much.

Sub CI_calculation()
'
' CI_calculation Macro
'

'
    ActiveSheet.Shapes("Button 7").Select
    Selection.Characters.Text = "CI"
    With Selection.Characters(Start:=1, Length:=2).Font
        .Name = "Arial"
        .FontStyle = "Regular"
        .Size = 10
        .Strikethrough = False
        .Superscript = False
        .Subscript = False
        .OutlineFont = False
        .Shadow = False
    End With
    Range("D7").Select
    ActiveCell.FormulaR1C1 = "=SQRT(1/RC[-1])"
    Range("E7").Select
    ActiveCell.FormulaR1C1 = "=RC[-3]-1.96*RC[-1]"
    Range("F7").Select
    ActiveCell.FormulaR1C1 = "=1+1.96*RC[-2]"
    Range("G8").Select
End Sub