fit data to distribution issue

Dear All;

I am trying to fit data to a normal distribution and plot pdf but pdf plot shows several lines , i do not know why it is coming , could you help.

figure is attached

[Mustafa Al-Nasser]

sorry this figure

[Turlough Hughes]

What code did you use?

[Mustafa Al-Nasser]

Thank you Hughes for your cooperation

this is the code i use

input1=input(1:1704,:)
input1= smoothdata(input1,'gaussian',5);

input2=input(1705:3533,:)
input2= smoothdata(input2,'gaussian',5);

input3=input(3534:5250,:)
input3= smoothdata(input2,'gaussian',5);


figure(3);
 plot(input1);
title('smoothData');
figure(4);
 plot(input2);
title('smoothData');
figure(5);
 plot(input3);
title('smoothData');


pd1 = fitdist(input1,'Normal')
pd2 = fitdist(input2,'Normal')
pd3 = fitdist(input3,'Normal')

y1 = pdf(pd1,input1);
y2 = pdf(pd2,input2);
y3 = pdf(pd3,input3);


plot(input1,y1,'LineWidth',2)
hold on
plot(input2,y2,'LineWidth',2)
plot(input3,y3,'LineWidth',2)

[Turlough Hughes]

Can you provide the data also so we can replicate what you have done, ie the variable input

[Mustafa Al-Nasser]

I extracted the related data part

Many thanks

Answer 1

[Raunak Gupta]

Hi,

From the code and data provided on question and comment, I see that the output you are plotting is not in sorted order. So basically, what you are currently seeing is the connected line between all the data points which is going in the direction of how the points are arranged in the input vector. For seeing a continuous line either you can sort both the input1 and y1 before plotting (And similarly for other two pairs) or instead of line you can plot circles for every datapoint. This will give correct visualization. Both approaches can be done like below:

% Sorting the input1 and y1 simultaneously 
[input1sorted, ind] = sort(input1);  
y1sorted = y1(ind); 
plot(input1sorted, y1sorted,'LineWidth',2); 

% plotting only dot for each datapoints 
plot(input1,y1,'o');