Assignment #6: Matrix Operations and Construction

 


1.) 

A <- matrix(c(2, 0, 1, 3), ncol = 2) and B <- matrix(c(5, 2, 4, -1), ncol = 2) , ncol = 2 to tell r to create a matrix with 2 columns and fill the numbers in with "c()".

A + B adds the numbers in that same spot,  for example the first numbers 1,1 is 2 and 5 = 7 because you are adding.

A - B subtracts the numbers in that same spot, for example the first numbers 1,1 is 2 and 5 = -3 because you are subtracting.

D <- diag(c(4, 1, 2, 3,)) creates a diagonal matrix where numbers go from top left to bottom right. So its telling R to create a matrix and put 4, 1, 2, 3 in a diagonal. 

E <- cbind(c(3, 2, 2, 2, 2), diag(3, 5, 5)[,2:5]) this code tells R to create a diagonal with 3's in a 5x5 with diag(3, 5, 5) and [,2:5] is getting rid of the first column and keeping columns 2 through 5. What cbind does it combine the custom column which is (3, 2, 2, 2, 2) in front of the 2-5 columns we kept. 

Comments

Post a Comment

Popular posts from this blog

Assignment #5: Matrix Algebra in R

Image
 1.) det(A) works because "A" which is 10x10 is a square so when det(A) is returned it is 0 meaning it is singular. That is why solve(A) does not work, it cannot invert a singular matrix. A zero determinant means the matrix is singular, so it does not have an inverse.  2.) Operations on B fail because "B" is 10x100, which is not a square, and determinants and inverses are defined by square matrices, hence why it did not work. A matrix has an inverse if two things are true its a square where it has the same rows and columns and its determinant is ≠ 0 3.) Since A has no inverse and B is not a square, both can still be used in a matrix multiplication with "%%". In numeric stability, if a determinant is close to 0 which is an example of A from solve() it can be unreliable due to rounding error.
Read more

Module #3 Assignment #3 Analyzing 2016 data "Poll" Data in R

Image
  1.) Looking at the candidates' (Names) key patterns, I noticed that CBS was shown more throughout the candidates. Donald also has the highest poll numbers. Ted also has a mix of CBS and ABC, but more CBS.  2.) Using made-up data does have its limitations. This can introduce bias and distortion, as evident in the data. CBS is more used compared to ABC.  3.) In a real analysis, I would collect data by creating a survey and inserting polls in there. I could include poll questions that ask about candidate preferences or approval ratings, then record and organize the responses.
Read more