stepwise mean value of array

Hi!

    % a= [1 2 5 6 4 7......]

how to get the mean value :

mean_a =[mean(a(1),a(110)),mean(a(2),a(120)), mean(a(3),a(130))............]

thanky

[Image Analyst]

What do you mean by mean(a(1),a(110))? Is that the mean of all elements from 1 to 110, like this: mean(a(1:110))?

[Rica]

Hi!

that means:the mean value of element 1 and element 100, nad the mean value of element 2 and element 200 an so on ..... thanks

Answer 1

[Jan]

x      = rand(1, 1000);
index1 = 1:10;
index2 = 100:100:1000;
result = (x(index1) + x(index2)) * 0.5;

Answer 2

[Dian Permatasari]

if the calculation of some matrix, you can use:

B=mean([A(1) A(2) A(3) ...])

Answer 3

[Walter Roberson]

N = 7;            %or as appropriate
LB = 1 : N;       %the lower bounds for the means
UB = (1:N)*100;   %or as appropriate for the upper bound

S = cumsum(a);    %the trick!
mean_a = (S(UB) - S(LB)) ./ (UB - LB + 1);

Answer 4

[Andrei Bobrov]

"...the mean value of element 1 and element 100, and the mean value of element 2 and element 200 an so on..." :

k = 100:100:numel(a);
mean_a = mean(a([(1:numel(k))', k']),2);