# Scott MacKenzie

### York University

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**Content Feed**

Calculating and add the std error bar from the mean values

You can't calculate the standard error from the means. You need the raw data. If the raw data (used to calculate the means) ar...

21 days ago | 0

| accepted

Separating table data by year

Here's what I put together using random temperatures between 30 and 100 over the period of interest. Since the temperatures are...

27 days ago | 0

Question

R2022a problem: Line number missing in error message sent to Command Window.

With R2022a, line numbers are sometimes omitted in error messages. Here's an example using a trivial script: If I run the sa...

30 days ago | 1 answer | 5

### 1

answerI have 2 columns in a matrix. 1st column has the dates. 2nd column has the values. How do I grab all values from 2nd column associated with its date from the 1st column??

Something like this will work: % test data d = { '4/1/18', 6; '4/2/18', 22; '4/2/18', 4; '4/3/18', 2; '4/3...

1 month ago | 1

Set to zero values in matrix in between two lines

You can vectorize the inner loop: % values of the matrix = 0 in between the two lines for ii=1:width A(floor(s1*ii+b1):fl...

1 month ago | 0

What is the code to count the number of word in the text file?

There are a few ways to set this up. Here's one using line-by-line processing and a loose definition of a word as a space-delim...

1 month ago | 0

how to plot surface graph in matlab?

The surf function is probably what you want: (Note that csvread is "not recommended".) x = 350:390; y = linspace(0.001, 0.03...

1 month ago | 1

| accepted

Repeated measures ANOVA with 2 variables with different levels

Change rm = fitrm(dv, 'uniR - texB ~ 1 ', 'WithinDesign', withinDesign); to rm = fitrm(dv, 'uniR-texB ~ 1 ', 'WithinDesign', ...

1 month ago | 0

| accepted

Dot indexing is not supported for variables of this type

Change xApp = av_train; data=xApp (: , 1); type = 1; feature=featureExtraction(data,'mean',type); to xApp = av_train; dat...

1 month ago | 0

| accepted

Histogram function plots different colours from those requested

The histogram function uses a face alpha of 0.6 by default. That's why the colors appear a bit lighter than the values from your...

2 months ago | 1

How to label each line in the plot

The main problem in the image is that the values are superimposed. This can be fixed by using an index into the Values array fo...

2 months ago | 0

Finding minimum output value for same inputs in a table

Is your table consistently organized as in the image; i.e., 36 rows repeating with the same values execpt for the last column (f...

2 months ago | 0

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draw oriented rectangle around a blob

Something like this seems to work: img = imread('testimage.jpg'); bw = imbinarize(im2gray(img),'adaptive','Sensitivity',0.45);...

2 months ago | 0

| accepted

How do I filter a signal, using FIR filters.

You could perhaps use a butterworth bandpass filter: (Note: Requires Signal Processing Toolbox) t = 0:1/8000:1023/8000; w = 0...

2 months ago | 1

| accepted

Duration of generated sound not correct

Change sound(y); to sound(y,Fsam); The sound function assumes a sampling rate of 8192 Hz. If a different sampling rate is u...

2 months ago | 0

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How do i plot an audio file with an interval in ms?

Using the sample frequency of the audio data (Fs), this code will extract and plot the first 20 ms: [x, Fs] = audioread('AudioS...

2 months ago | 0

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Designing a Butterworth Filter

Here's a solution, but it requires MATLAB's Signal Processing Toolbox. Given, sRate, the sample rate of your data, fc, the de...

2 months ago | 1

Find files of a certain extension and populate a structure field with those file names.

Your second command is wrong. The dir command returns a structure. You don't need to append ".file_names". The filenames are ...

2 months ago | 0

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How to estimate the Statistical Significance of a Correlation When the Data Are Serially Correlated in matlab?

MATLAB's corrcoef function provides the correlation (r) as well as the significance (p) of the correlation. For your data set, ...

2 months ago | 0

Rearranging tables based on elements

For tables, an effective way to "transpose" (switch rows with columns, including variable names) is using the rows2vars function...

2 months ago | 0

Finding student t critical value...

Here's demo code using tinv to produce the t-critical values for a two-sided test with independent samples (i.e., between-subjec...

2 months ago | 0

How to draw a pulse train

It seems you want to replace the negative portion of the pulse with zeros. Like this, perhaps: fy=100; wy=2*pi*fy; duy=0.02;...

2 months ago | 0

How to generate Pattern in MATLAB

Here's code to generate the patterns in the image posted: f = figure('color', 'w', 'Units','normalized','Position',[.25 .3 .4 ....

2 months ago | 0

How do I make the movmean calculate the moving average at the start- and endpoints of an array but in conjunction to each other?

This seems to do the trick: A = [0 2 4 1 3 5 7]; M = movmean(A,[2 1]); M2 = movmean([A A A],[2 1]); n = numel(A); M2 = M2...

2 months ago | 0

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How to rank data and set corresponsing values

Assuming the rankings are just used to explain your final goal, the following seems to work: M1 = [0.004130861 0.001492476 -0...

2 months ago | 0

How can I save the output figure into an image file?

A easy way is to use exportgraphics, introduced in R2020a: f = figure; imshow(...); exportgraphics(f, 'filename.jpg'); % or ....

2 months ago | 0

Generate acoustic signal with difference rise time and fall time

Here's a simple approach that provides separate control for the rise or attack time (n1), the sustain time (n2), and the decay o...

2 months ago | 0

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Store identical rows in specified column

This seems to answer your question. There are 41 uniques IDs in the second column of your data set. The code below extracts th...

2 months ago | 0

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Save marked point on plot

OK, this seems to to work. The x-y coordinates of the marked points are output to the command window (along with the figure num...

2 months ago | 0

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Save marked point on plot

Since you haven't provided any data or code, this is a rough answer only: [pks, locn] = findpeaks(-y, 'MinPeakProminence', 0.1)...

2 months ago | 0