# Sample exam questions

### Test Your MATLAB Knowledge for the MathWorks Certified MATLAB Associate Exam

Which command will return the corner elements of a 10-by-10 matrix A?

A.  `A([1,end], [1,end])`
B.  `A([1,1], [end,end])`
C.  `A({[1,1], [1,end], [end,1], [end,end]})`
D.  `A(1:end, 1:end)`

Which command will return the fraction of positive numbers in a 10-by-10 matrix A?

A.  `A(A > 0)/A`
B.  `numel(A > 0)/numel(A)`
C.  `sum(A > 0)/prod(size(A))`
D.  `nnz(A > 0)/numel(A)`

Which command will delete (completely remove) the last cell of a cell-array C?

A.  `C{end} = [];`
B.  `C[end] = [];`
C.  `C(end) = [];`
D.  `C{end} = {[]};`

Which command will create a plot of acceleration vs. time (i.e., a vector time on the x-axis and a vector acceleration on the y-axis)?

A.  `plot(time, acceleration)`
B.  `plot(acceleration, time)`
C.  `plot([time, acceleration])`
D.  `plot([acceleration, time])`

Which command will give the standard deviation for each column in a 10-by-5 matrix Z?

A.  `std(Z(:))`
B.  `std(std(Z))`
C.  `std(Z(1:5, :))`
D.  `std(Z)`