MATLAB: How to convert the 8*8 matrix a to 4*4 matrix b using downsample

Question

downsample for raw and column and save the result in one matrix like b

for example:

a=

   [1 2 8 5 4 7 5 9;
   4 8 3 6 7 1 2 11;
   7 8 2 1 7 7 7 9;
   11 5 7 0 9 7 6 5;
   7 8 9 6 0 0 8 7;
   9 6 7 2 6 3 2 1;
   1 1 2 4 5 8 9 6;
   0 7 8 9 6 3 5 4]

b=

   1 8 4 5
   7 2 7 7
   7 9 0 8
   1 2 5 9

Answer 1

A(1:2:end,1:2:end)