Averaging waves which has NaN for some rows

Function Test()
//  Test Function
 
    //  Creates three waves to average
    Make/O Wave1={1, 2, NaN, 4, 5}
    Make/O Wave2={3, 2, 1, NaN, -1}
    Make/O Wave3={2, 2, 2, NaN, 2}
 
    //  Creates a wave reference wave to hold the three waves
    Make/O/FREE/WAVE AllWaves={Wave1, Wave2, Wave3}
    
    //  Averages the waves
    Wave AverageWave=AverageAllWaves(AllWaves)
    
    //  Displays the result
    DoWindow/K AverageTable
    Edit/N=AverageTable Wave1, Wave2, Wave3, AverageWave
End
 
 
Function/WAVE AverageAllWaves(AllWaves)
//  Averages all waves ignoring NaNs
Wave/WAVE AllWaves
 
    //  Calculates the number of waves to average. The waves should all have the same length
    Variable n=NumPnts(AllWaves)
    
    //  Checks that at least one wave exists
    if (n>0)
    
        //  Uses the first wave in the list to create the waves needed for the calculation
        Wave SingleWave=AllWaves[0]
        Duplicate/O/FREE SingleWave, NumTypeWave, DivisionWave, SumWave
        Duplicate/O SingleWave, AverageWave
    
        NumTypeWave=0
        DivisionWave=0
        SumWave=0
        AverageWave=0
    
        //  Counts through the waves one at a time
        Variable i=0
        for (i=0; i<n; i+=1)
    
            //  The next wave to add to the total sum
            Wave SingleWave=AllWaves[i]
        
            //  Checks if any of the values are NaN
            NumTypeWave=(NumType(SingleWave[p])!=2)
        
            //  Adds the value to the total, unless the value is NaN in which case 0 is added
            SumWave+=(NumTypeWave[p]==1 ? SingleWave : 0)
        
            //  Increases the number to divide the sum with by one, unless the value is NaN in which case 0 is added
            DivisionWave+=NumTypeWave[p]
        endfor
 
        //  Divides the sum by the number of valid data points
        AverageWave=SumWave/DivisionWave
        
        //  Returns the average
        Return AverageWave
    endif
end