compare related, consecutive rows, looking for a final status

I am a teacher. I use a tracking program called Montessori Records Express. This program can output student data to an Excel spreadsheet.
When I plan a lesson for a child, the following row is generated.
name=student name, lesson=lessonNumber, date, status=planned

When the student does the associated work but doesn’t get it completely right, I update the status and the following row is generated:
name=student name, lesson=lessonNumber, date, status=improving

If the student, however, gets it right the first time, or corrects his errors, I update the status and the following row is generated:
name=student name, lesson=lessonNumber, date, status=mastered.

name date lesson status
John 11-1-2010 1 planned
John 11-2-2010 1 mastered
John 11-3-2010 2 planned
John 11-4-2010 2 improving
John 11-4-2010 2 mastered
John 11-4-2010 3 planned
John 11-3-2010 4 planned
John 11-4-2010 4 improving

Parents have access to this report. After a while, a student’s report can have hundreds of rows. What they and I would like to have is a way to find all of the lessons that were planned but not mastered to see what work hasn’t been finished, either never followed-up on or done but with errors. In the above example, lesson 1 and 2 would be filtered out but the rows for lessons 3 and 4 would remain to show that the child received the lesson but had not finished the work without errors yet.
Thanks for your help. This would really help the parents to support their children’s work.
Tom

Please come back to me if this goes over your head but this VBA code will do what you need providing the following is true:

Row 1 is for column headers
Column A is Name
Column B is Date
Column C is Lesson
Column D is Status

Sub HideRows()
'Determine Last Row
Range("A1").Select
Selection.End(xlDown).Select
LastRow = ActiveCell.Row

'Loop through all rows and put lesson number in column E
'If lesson has been mastered
Dim cell As Range
For x = 2 To LastRow
LessonNo = Cells(x, 3).Value
If Cells(x, 4).Value = "mastered" Then
Cells(x, 5).Value = LessonNo
End If
Next

'Now loop through rows again and if the lesson number has been
'entered into column E then hide that row
For x = 2 To LastRow
LessonNo = Cells(x, 3).Value
If Application.WorksheetFunction.CountIf(Range("E:E"), LessonNo) = 1 Then
ActiveSheet.Rows(x).Hidden = True
End If
Next

'Tidy column E so it doesn't show the lessonnumbers previously added by
'Macro
Range("E:E").ClearContents
End Sub

Sub UnhideAllRows()
Cells.Select
    Selection.EntireRow.Hidden = False
    End Sub

Thanks. That's a big help. I'll give those a try.