Ttest with two matrix

Hi!

I have two datasets, both with 5 cell lines and 20 000 genes (20000x5). I now want to compare these two, since one is a control group and one has been treated with drugs. My plan was to use ttest, but it is not working. A error messages comes up that says:

Undefined operator '-' for input arguments of type 'table'.

Error in ttest (line 71)

x = x - m;

I have load up the two excel files by using spreadsheetDatastore, could that be the problem?

Thankful for any help :)

Answer 1

[Samayochita]

Hi Mimmi,

It appears that the error is occurring because the “ttest” function in MATLAB expects numeric arrays as input, whereas the data is currently in the form of a table, which is the typical output format from “spreadsheetDatastore”.

To resolve this, the table data can be converted into a numeric array using the “table2array” function before passing to “ttest”.

Assuming the data is loaded as:

ds1 = spreadsheetDatastore('control.xlsx'); 
ds2 = spreadsheetDatastore('treated.xlsx'); 

Read the data as:

tbl1 = read(ds1); 
tbl2 = read(ds2); 

Now, convert the tables to numeric arrays (if the tables only contain numeric data):

X = table2array(tbl1); 
Y = table2array(tbl2); 

Finally, apply “ttest” by passing X and Y to the “ttest” function.

For more information on the functions mentioned above, please refer to following the documentation links:

https://www.mathworks.com/help/matlab/ref/matlab.io.datastore.spreadsheetdatastore.html

https://www.mathworks.com/help/stats/ttest.html

https://www.mathworks.com/help/matlab/ref/table2array.html

https://www.mathworks.com/help/matlab/ref/matlab.io.datastore.read.html