Mean and Median of Values in a matrix

I want to take the mean and median of the mean and median of four columns and then store those values in a separate file to plot the graph later. I have 30,000 rows, with four columns as below: The below is an example of the data points. The first column has a different range of flow rates. I want to take the mean and median of all columns, considering that this average will be based on the set range of 1st column, for example, range 800-900, 900-1000, 1000-11000, and so.

The results will be stored in some other file so that I can make the graph. load.

Data file example below:

Flow Rate Entrance Pressure Exit Pressure Pressure Difference

820 7.52 6.5 1.02

820 7.49 6.55 .94

820 7.51 6.52 0.99

820 7.57 6.58 0.99

820 7.58 6.58 1

819 7.54 6.59 0.95

907 9.27 7.8 1.47

915 9.3 7.78 1.52

918 9.35 7.91 1.44

917 9.46 7.97 1.49

1011 11.2 9.44 1.76

1005 11.38 9.58 1.8

1005 11.32 9.54 1.78

1005 11.39 9.49 1.9

1005 11.32 9.51 1.81

1005 11.26 9.44 1.82

Any help is appreciated.

Thanks

[Dyuman Joshi]

You can use logical indexing to find the required data. For example -

y=flowrate(flowrate>=800&flowrate<900);
mean(y)
median(y)

You can use for loop as well to automate the process.

[Kawalpreet Kaur]

Thanks Dyuman. it worked!

Can you please help me on how to store these values for four columns in the form of a matrix in a separate text or excel? So that I can plot a graph from the output matrix.

Appreciate your help.

Thanks!

[Dyuman Joshi]

I'm assuming you want to do seperate matrices for mean and median values? And that you want to use for loops as well?

Answer 1

[Dyuman Joshi]

I am giving you an example for one variable.

meanvalue=[];
medianvalue=[];
for i=800:100:lastvalue
    y=flowrate(flowrate>=i&flowrate<(i+100));
    meanvalue=[meanvalue mean(y)];
    medianvalue=[medianvalue median(y)];
end

Are the groups in the same range here? i.e 800-900 group in flowrate corresponds to 7-8 group in extrance pressure, 6-7 in exit pressure and 0.9-1 in pressure difference, for all ranges?

If they are not, the output matrix you want (with 4 columns) will not be possible.

[Kawalpreet Kaur]

Yes, the range of the first column is the decision factor to take the mean and median of corresponding next three columns.

[Kawalpreet Kaur]

I didn't get this..........

meanvalue=[];

medianvalue=[];

for i=800:100:lastvalue

y=flowrate(flowrate>=i&flowrate<(i+100));

meanvalue=[meanvalue mean(y)];

medianvalue=[medianvalue median(y)];

end

[Dyuman Joshi]

Apologies for the late reply, I didn't get the notification of your reply.

I'll explain the whole thing.

1 - I have defined empty array to update and obtain the corresponding mean and median values you require.

2 - Since we are comparing Flowrate in the range of 100 (800-900, 900-1000, ...), I made it the varying parameter to the for loop.

y will be the corresponding values obtained of the range.

3 - Then we use mean() and median() on the data and modify our matrix to include the acquired data.

[Kawalpreet Kaur]

Hi Dyuman, Thank you for your help. As you suggested, I did some changes,and got the required output.

Thank you for your help.

[Dyuman Joshi]

You are welcome. If your problem got solved, please accept my answer!

Answer 2

[Kawalpreet Kaur]

Yes, you are right.

For example,

Mean

818 7.14 6.10 1.04

915 8.15 7.00 1.15

.

.

.

and so on until last range.

Median

818 7.25 6.00 1.025

905 8.05 7.01 1.04

.

.

.

and so on until last range.

Answer 3

[Steven Lord]

Take a look at the groupsummary function.

[Kawalpreet Kaur]

Hi Steven,

I checked the groupsummary function. I have no specific function variable. I have a range of numbers in column 1, then, accordingly, the mean and median of the col1, col2, col3, and col4, based on the set range of col1.

I am new to Matlab and have not had enough knowledge. Your help would be much appreciated.

Thank you.