Could somebody explain why I am getting the error message? thanks!

MATLAB R2016b-academic use Dalila HOME APPS EDITOR .ositive integersurlug ical values..x New Variable Analyze Code Find Fies Run and Time Set Path Request Suppot New New New Open Campare Import Save Scripl Live Scrip! Favarites Simuink Layau Add-Ons Help Dats, Workspace . Clear warkspace Clear Cammands Parallel Learn MATLAR Editor-CiUsers dalil Documents MATLAB'hw5.m Command Windnw X remain survey.m 57- 58 59- 60- 61 y=-1:0.1:1 z 2:0.1:2 Array indices must be positive integers o values. ; xval-length (x); yval-length (y) zval-length (z); T-zeros (xval, yval, zval) Error in hw5 (line 77) p2b (1+3)= sum ( T ( i, j , :))/zval; 64 for j-1:yval 65-Hl for k= 1: zva T(i,j,k)(i) 2 + 2 y(j).2 +3*z(k).2 67 68-- 69 70 71 72 73 74- 75 for i-1: xval end end end p2a-T; p2b- zeros (xval,yval); % Matrix with dimensions len for j-1:yval p2b ( 1 ,j)-sum (T(i,j, :))/7val; 78 end script Ln 60 Col 15 2/15/2019 1 MATLAB R2016b-academic use Dalila HOME APPS EDITOR .ositive integersurlug ical values..x New Variable Analyze Code Find Fies Run and Time Set Path Request Suppot New New New Open Campare Import Save Scripl Live Scrip! Favarites Simuink Layau Add-Ons Help Dats, Workspace . Clear warkspace Clear Cammands Parallel Learn MATLAR Editor-CiUsers dalil Documents MATLAB'hw5.m Command Windnw X remain survey.m 57- 58 59- 60- 61 y=-1:0.1:1 z 2:0.1:2 Array indices must be positive integers o values. ; xval-length (x); yval-length (y) zval-length (z); T-zeros (xval, yval, zval) Error in hw5 (line 77) p2b (1+3)= sum ( T ( i, j , :))/zval; 64 for j-1:yval 65-Hl for k= 1: zva T(i,j,k)(i) 2 + 2 y(j).2 +3*z(k).2 67 68-- 69 70 71 72 73 74- 75 for i-1: xval end end end p2a-T; p2b- zeros (xval,yval); % Matrix with dimensions len for j-1:yval p2b ( 1 ,j)-sum (T(i,j, :))/7val; 78 end script Ln 60 Col 15 2/15/2019 1