generate a set data with random errors

we can generate a set of data with a random error about some mean value with the command

    >>num=100;
    >>spr=0.1;
    >>data=5.0=spr*sign(1.0-2.0*rand(1,num)).*rand(1,num);

a)what is the last line doing?

b)write a program which computes the mean and standard deviation of the data.

plz help me.!!!!!!

[Andrei Bobrov]

as?

data=5.0 + spr*sign(1.0-2.0*rand(1,num)).*rand(1,num);

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

Answer 1

[Andrei Bobrov]

er1 - random error - uniform distribution from -0.1 to 0.1

spr = .1;
er1 = spr*sign(1.0-2.0*rand(1,num)).*rand(1,num);

OR

er1 = spr*(2*rand(1,num) - 1)

[henny]

i am unable to understand

[Andrei Bobrov]

please read about 'rand': http://www.mathworks.com/help/techdoc/ref/rand.html