# njj1

### National Institute of Standards and Technology

**Statistics**

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**Content Feed**

Question

Scatter plot changes markers when using 'filled' option

I am using scatter plot and for some reason when I use the "filled" option, the marker shapes change to squares. Here is an exam...

1 year ago | 1 answer | 0

### 1

answerDate numbers in double to datestring matrix

You cannot put date strings and numerical data into a single matrix. You could use a cell if you wanted. For example: X_new...

3 years ago | 0

| accepted

How do I make an array of elapsed times?

OK, so this sounds like it's inside a for loop, in which case you could try something like this: for runs=number_of_runs:-1...

3 years ago | 0

How to display velocity for each loop at 20 seconds?

You have an error in your code: fprint('%.0m/s\n', vj(,2) This code should work for you: Time=20; %Time the jumper ...

3 years ago | 0

| accepted

How to solve non linear equation for one variable?

If you want to solve for multiple values of temp and yieldstress, you will have to use a for loop. for i=1:numel(temp) ...

3 years ago | 1

| accepted

How to plot a pdf and cdf for my code

If you want to compute the pdf for a normal distribution over a range of values, you must input a vector of possible values sort...

3 years ago | 0

Finding the Maximum of 6 matrices

You can use max(X,[],dim) to specify the dimension from which to compute the maximum value. For example, if you let dim=2, then ...

3 years ago | 0

How do I make a gradient for my data

The gradient function in Matlab takes in two main arguments: the independent variable(s) step size and the data as a function of...

3 years ago | 0

How would i run different events from the same .txt file?

You should import the entire matrix and then begin the splitting process. A = dlmread('Nest.txt',' '); %this assumes there ...

3 years ago | 0

| accepted

In a matrix how to replace zero by NaN.?

Try this: A(A==0) = NaN;

3 years ago | 7

| accepted

this is my equation using matlab , i can't get it manually.

This looks like it's the distance from each (x,y) pair to every other (x,y) pair. A_{i,j} = \sqrt{(x_i - x_j)^2}, where x = (...

3 years ago | 0

| accepted

Classification of a whole matrix

You could turn the matrix into a vector (e.g., X = X(:)), then use the resulting vector as input to the classification learner. ...

3 years ago | 1

sorting the outputs of clusters

What do you mean "sort". You could save them to different variables. For example, if you main matrix is called X and you have cl...

3 years ago | 0

How to write a range of numbers in MATLAB?

ranges = [0,12,20:10:110]; %end points of requested speeds for i = 1:numel(ranges)-1 v{i} = V((V>ranges(i) & (V<=ra...

3 years ago | 1

Kmeans clustering in k=10

1) Randomly initialize 10 cluster centroids. This can be done by simply randomly selecting 10 points from your dataset. 2) Co...

3 years ago | 0

Help graphing this equation

You need to have an independent variable (e.g., when plotting y vs. x, x is the independent variable). So if you want to plot ep...

3 years ago | 1

| accepted

How to write a range of numbers in MATLAB?

v1 = V((V>0) & (V<=60)); numV1 = numel(v1); v2 = V((V>60) & (V<=80)); numV2 = numel(v2); v3 = V((V>80) & (V<=110)); numV...

3 years ago | 0

How to assign fields from a Struct into every 5th column of a Matrix

It is often helpful to step through your code and examine the variables at each step. One problem could be the shape of your var...

3 years ago | 0

What is the easiest way to create a textbox?

The annotation command is quite useful and can save time for sure. Unfortunately, it does not have any 'top right' commands, so ...

3 years ago | 0

How to compare two different sample size on basis of datapoints in same interval?

You can use a histogram, but with the property 'Normalization' set to 'pdf'. This will plot an estimated probability density fun...

3 years ago | 0

| accepted

Merging array into matrix of unequal size

Why not create the matrix M such that it's size is [numel(x), num_of_desired_columns]? For example, if num_of_desired_columns = ...

3 years ago | 0

Math problem for code

Try using diff(S,1,dim) to get the difference between sequential elements in the matrix S. Each entry in diff(S) is (x_{n} - x_{...

3 years ago | 0

| accepted

Question

Why doesn't 'HeaderLines' work in the readtable command?

I am importing some excel files into Matlab using the readtable command. There are a couple of header lines in the file that I w...

3 years ago | 2 answers | 1

### 2

answersWarning: Matrix is singular to working precision. how to solve?

There are ways of getting around a singular matrix, but they are a little ad hoc. have you tried QR decomposition ([Q,R] = qr(A)...

3 years ago | 0

Shading between two curves

You can try using the "fill" function (could also use "patch"). Just off the top of my head, if you can compute the area between...

3 years ago | 0

How to compare the values of 2 arrays vs each other?

What do you mean by "similar"? If you want simply see the number of entries that are the same, then this could do the trick: ...

3 years ago | 0

| accepted

How to keep an element fixed until it fits a condition?

Can you clean up the code a little? It's not clear where the loops begin and end... A couple more questions/comments. 1) How...

3 years ago | 0

I would like to know if my function is correct

You actually need not go through the whole for loop to do this. First off, I assume the number of entries in x is equal to the n...

3 years ago | 0

How to see how a dataset changes over time with PCA.

It's hard to know exactly what you are hoping to achieve here. When using pca(x) in Matlab, we are assuming that "rows of X corr...

3 years ago | 0

Question

AR prediction leads fitted data

I am using aryule to construct a predictive AR filter. After I filter the data, the predicted values "lead" the actual data by o...

3 years ago | 0 answers | 0