"Index in position 1 is invalid. Array indices must be positive integers or logical values."

I get the entitled error when ever i run the code below

nu=sum((i-(n+1)/2).*Y(i,:)

for the equation

and also the same error for

de=sqrt(n^3*(sum(Y(i,:)-mean(Y(i,:)))^.2))

for the equation

where first is the numerator and second is the denominator of D, "test for normality was given by D’Agostino"

full code

y1=[51 27 37 42 27 43 41 38 36 26 29]';

y2=[36 20 22 36 18 32 22 21 23 31 20]';

y3=[50 26 41 32 33 43 36 31 27 31 25]';

y4=[35 17 37 34 14 35 25 20 25 32 26]';

y5=[42 27 30 27 29 40 38 16 28 36 25]';

Y=[y1 y2 y3 y4 y5]

Y=sort(Y)

[n p]=size(Y)

nu=sum((i-(n+1)/2).*Y(i,:))

de=sqrt(n^3*(sum(Y(i,:)-mean(Y(i,:)))^.2))

D=nu./de

YY=sqrt(n)*(D-inv(2*sqrt(pi)))/0.02998598

[Rik]

Without the full code you are using it is difficult to provide a working solution. Try to make a MWE so we can run your code without any other dependencies and can reproduce your issue.

Currently it is not possible to tell if you are shadowing the sum function with a variable named sum, or if your i variable is not properly defined.

[Rik]

You didn't define i yourself, so now Matlab treats it as the imaginary unit. I don't have a clue what you're trying to do, but it seems you should read the documentation for the symbolic computation toolbox, or rewrite your expression to a normal Matlab computation.

Answer 1

[Preethi]

Initialize variable i with 1, before using it

i=1;

[Rik]

Although this modification will make this code run without error, this will not return the solution for the mathematical expression. I don't understand the notation (specifically the equal sign inside the sum), but I'm sure this will not solve the problem.

[Mustafa Kamal]

now i have made some changes in the code however i is giving wrong answer

y1=[47.8,46.4,46.3,45.1,47.6,52.5,51.2,49.8,48.1,45.0,51.2,48.5,52.1,48.2,49.6,50.7,47.2,53.3,46.2,46.3]';

y2=[48.8,47.7,46.8,45.3,48.5,53.2,53,50,50.8,47,51.4,49.2,52.8,48.9,50.4,51.7,47.7,54.6,47.5,47.6]';

y3=[49,47.7,47.8,46.1,48.9,53.3,54.3,50.3,52.3,47.3,51.6,53,53.7,49.3,51.2,52.7,48.4,55.1,48.1,51.3]';

y4=[49.7,48.4,48.5,47.2,49.3,53.7,54.5,52.7,54.4,48.3,51.9,55.5,55,49.8,51.8,53.3,49.5,55.3,48.4,51.8]';

Y=[y1 y2 y3 y4];

Y=sort(Y)

n=length(Y)

T=[];

W=[];

for i=1:n

T=[T; ((i-(n+1)/2).*Y(i,:))]

W=[W; sqrt(n^3*((Y(i,:)-mean(Y)).^2))]

end

nu=sum(T)

de=sum(W)

D=nu./de

YY=sqrt(n).*(D-inv(2*sqrt(pi)))./0.02998598

where are the correct answer for the above question is

D=[.2848 .2841 .2866 .2851]

and

YY=[.4021 .2934 .6730 .4491]

please help anyone to resolve my issue.