AWK script- Not showing data - variables

Question

I'm trying to create a variable to sum columns 26 to 30 and 32.
SO far I have this code which prints me the hearder and the output format like I want but no data is being shown.
#! /usr/bin/awk -f
BEGIN { FS="," }
NR>1 {
TotalPositiveStats= ($26+$27+$28+$29+$30+$32)
}
{printf "%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%.2f %,%s,%s,%.2f %,%s,%s,%.2f %,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s, %s\n",
EndYear,Rk,G,Date,Years,Days,Age,Tm,Home,Opp,Win,Diff,GS,MP,FG,FGA,FG_PCT,3P,3PA,3P_PCT,FT,FTA,FT_PCT,ORB,DRB,TRB,AST,STL,BLK,TOV,PF,PTS,GmSc,TotalPositiveStats
}
NR==1 {
print "EndYear,Rk,G,Date,Years,Days,Age,Tm,HOme,Opp,Win,Diff,GS,MP,FG,FGA,FG_PCT,3P,3PA,3P_PCT,FT,FTA,FT_PCT,ORB,DRB,TRB,AST,STL,BLK,TOV,PF,PTS,GmSc,TotalPositiveStats" }#header
Input data:
EndYear,Rk,G,Date,Years,Days,Age,Tm,Home,Opp,Win,Diff,GS,MP,FG,FGA,FG_PCT,3P,3PA,3P_PCT,FT,FTA,FT_PCT,ORB,DRB,TRB,AST,STL,BLK,TOV,PF,PTS,GmSc
1985,1,1,10/26/1984,21,252,21.6899384,CHI,1,WSB,1,16,1,40,5,16,0.313,0,0,,6,7,0.857,1,5,6,7,2,4,5,2,16,12.5
1985,2,2,10/27/1984,21,253,21.69267625,CHI,0,MIL,0,-2,1,34,8,13,0.615,0,0,,5,5,1,3,2,5,5,2,1,3,4,21,19.4
1985,3,3,10/29/1984,21,255,21.69815195,CHI,1,MIL,1,6,1,34,13,24,0.542,0,0,,11,13,0.846,2,2,4,5,6,2,3,4,37,32.9
1985,4,4,10/30/1984,21,256,21.7008898,CHI,0,KCK,1,5,1,36,8,21,0.381,0,0,,9,9,1,2,2,4,5,3,1,6,5,25,14.7
1985,5,5,11/1/1984,21,258,21.7063655,CHI,0,DEN,0,-16,1,33,7,15,0.467,0,0,,3,4,0.75,3,2,5,5,1,1,2,4,17,13.2
1985,6,6,11/7/1984,21,264,21.72279261,CHI,0,DET,1,4,1,27,9,19,0.474,0,0,,7,9,0.778,1,3,4,3,3,1,5,5,25,14.9
1985,7,7,11/8/1984,21,265,21.72553046,CHI,0,NYK,1,15,1,33,15,22,0.682,0,0,,3,4,0.75,4,4,8,5,3,2,5,2,33,29.3
Output expected:
EndYear,Rk,G,Date,Years,Days,Age,Tm,Home,Opp,Win,Diff,GS,MP,FG,FGA,FG_PCT,3P,3PA,3P_PCT,FT,FTA,FT_PCT,ORB,DRB,TRB,AST,STL,BLK,TOV,PF,PTS,GmSc,TotalPositiveStats
1985,1,1,10/26/1984,21,252,21.6899384,CHI,1,WSB,1,16,1,40,5,16,0.313,0,0,,6,7,0.857,1,5,6,7,2,4,5,2,16,12.5,35
1985,2,2,10/27/1984,21,253,21.69267625,CHI,0,MIL,0,-2,1,34,8,13,0.615,0,0,,5,5,1,3,2,5,5,2,1,3,4,21,19.4,34
1985,3,3,10/29/1984,21,255,21.69815195,CHI,1,MIL,1,6,1,34,13,24,0.542,0,0,,11,13,0.846,2,2,4,5,6,2,3,4,37,32.9,54
1985,4,4,10/30/1984,21,256,21.7008898,CHI,0,KCK,1,5,1,36,8,21,0.381,0,0,,9,9,1,2,2,4,5,3,1,6,5,25,14.7,38
1985,5,5,11/1/1984,21,258,21.7063655,CHI,0,DEN,0,-16,1,33,7,15,0.467,0,0,,3,4,0.75,3,2,5,5,1,1,2,4,17,13.2,29
1985,6,6,11/7/1984,21,264,21.72279261,CHI,0,DET,1,4,1,27,9,19,0.474,0,0,,7,9,0.778,1,3,4,3,3,1,5,5,25,14.9,36
1985,7,7,11/8/1984,21,265,21.72553046,CHI,0,NYK,1,15,1,33,15,22,0.682,0,0,,3,4,0.75,4,4,8,5,3,2,5,2,33,29.3,51
This script will be called like gawk -f script.awk <filename>.
Currently when calling this is the output (It seems to be calculating the variable but the rest of fields are empty)

Answer 1

awk is well suited to summing columns:
awk 'NR>1{$(NF+1)=$26+$27+$28+$29+$30+$32}1' FS=, OFS=, input-file > tmp
mv tmp input-file
That doesn't add a field in the header line, so you might want something like:
awk '{$(NF+1) = NR>1 ? ($26+$27+$28+$29+$30+$32) : "TotalPositiveStats"}1' FS=, OFS=,

Answer 2

An explanation on the issues with the current printf output is covered in the 2nd half of this answer (below).
It appears OP's objective is to reformat three of the current fields while also adding a new field on the end of each line. (NOTE: certain aspects of OPs code are not reflected in the expected output so I'm not 100% sure what OP is looking to generate; regardless, OP should be able to tweak the provided code to generate the desired result)
Using sprintf() to reformat the three fields we can rewrite OP's current code as:
awk '
BEGIN { FS=OFS="," }
NR==1 { print $0, "TotalPositiveStats"; next }
{ TotalPositiveStats = ($26+$27+$28+$29+$30+$32)
$17 = sprintf("%.3f",$17) # FG_PCT
if ($20 != "") $20 = sprintf("%.3f",$20) # 3P_PCT
$23 = sprintf("%.3f",$23) # FT_PCT
print $0, TotalPositiveStats
}
' raw.dat
NOTE: while OP's printf shows a format of %.2f % for the 3 fields of interest ($17, $20, $23), the expected output shows that the fields are not actually being reformatted (eg, $17 remains %.3f, $20 is an empty string, $23 remains %.2f); I've opted to leave $20 as blank otherwise reformat all 3 fields as %.3f; OP can modify the sprintf() calls as needed
This generates:
EndYear,Rk,G,Date,Years,Days,Age,Tm,Home,Opp,Win,Diff,GS,MP,FG,FGA,FG_PCT,3P,3PA,3P_PCT,FT,FTA,FT_PCT,ORB,DRB,TRB,AST,STL,BLK,TOV,PF,PTS,GmSc,TotalPositiveStats
1985,1,1,10/26/1984,21,252,21.6899384,CHI,1,WSB,1,16,1,40,5,16,0.313,0,0,,6,7,0.857,1,5,6,7,2,4,5,2,16,12.5,40
1985,2,2,10/27/1984,21,253,21.69267625,CHI,0,MIL,0,-2,1,34,8,13,0.615,0,0,,5,5,1.000,3,2,5,5,2,1,3,4,21,19.4,37
1985,3,3,10/29/1984,21,255,21.69815195,CHI,1,MIL,1,6,1,34,13,24,0.542,0,0,,11,13,0.846,2,2,4,5,6,2,3,4,37,32.9,57
1985,4,4,10/30/1984,21,256,21.7008898,CHI,0,KCK,1,5,1,36,8,21,0.381,0,0,,9,9,1.000,2,2,4,5,3,1,6,5,25,14.7,44
1985,5,5,11/1/1984,21,258,21.7063655,CHI,0,DEN,0,-16,1,33,7,15,0.467,0,0,,3,4,0.750,3,2,5,5,1,1,2,4,17,13.2,31
1985,6,6,11/7/1984,21,264,21.72279261,CHI,0,DET,1,4,1,27,9,19,0.474,0,0,,7,9,0.778,1,3,4,3,3,1,5,5,25,14.9,41
1985,7,7,11/8/1984,21,265,21.72553046,CHI,0,NYK,1,15,1,33,15,22,0.682,0,0,,3,4,0.750,4,4,8,5,3,2,5,2,33,29.3,56
NOTE: in OP's expected output it appears the last/new field (TotalPositiveStats) does not contain the value from $30 hence the mismatch between the expected results and this answer; again, OP can modify the assignment statement for TotalPositiveStats to include/exclude fields as needed
Regarding the issues with the current printf ...
{printf "%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%.2f %,%s,%s,%.2f %,%s,%s,%.2f %,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s, %s\n",
EndYear,Rk,G,Date,Years,Days,Age,Tm,Home,Opp,Win,Diff,GS,MP,FG,FGA,FG_PCT,3P,3PA,3P_PCT,FT,FTA,FT_PCT,ORB,DRB,TRB,AST,STL,BLK,TOV,PF,PTS,GmSc,TotalPositiveStats}
... is referencing (awk) variables that have not been defined (eg, EndYear, Rk, G). [NOTE: one exeception is the very last variable in the list - TotalPositiveStats - which has in fact been defined earlier in the script.]
The default value for undefined variables is the empty string ("") or zero (0), depending on how the awk code is referencing the variable, eg:
printf "%s", EndYear => EndYear is treated as a string and the printed result is an empty string; with an output field delimiter of a comma (,) this empty strings shows up as 2 commas next to each other (,,)
printf "%.2f %", FG_PCT => FG_PCT is treated as a numeric (because of the %f format) and the printed result is 0.00 %
Where it gets a little interesting is when the (undefined) variable name starts with a numeric (eg, 3P) in which case the P is ignored and the entire reference is treated as a number, eg:
printf "%s", 3P => 3P is processed as 3 and the printed result is 3
This should explain the 5 static values (0.00 %, 3, 3, 3.00 % and 0.00 %) printed in all output lines as well as the 'missing' values between the rest of the commas (eg, ,,,,).
Obviously the last value in the line is an actual number, ie, the value of the awk variable TotalPositiveStats.