Publications by Diana Plunkett
DPlunkett_Assignment3_605
Problem Set 1 (1) What is the rank of matrix A? \[A= \begin{bmatrix} 1 & 2 & 3 & 4\\ -1 & 0 & 1 & 3\\ 0 & 1 & -2 & 1\\ 5 & 4 & -2 & -3 \end{bmatrix} \] Finding det(A) can help. If det(A) \(\neq\) 0, then the rank is “full rank” which in this case is 4. First, convert to row echelon form. \(R_2 \rightarrow R_2 + R_1\) yields: \[ \begin{bmatrix...
6621 sym
605 Assignment2
Problem Set 1 Show that \(A^TA \neq AA^T\) in general. (Proof and demonstration.) To prove this, we will use proof by contradiction. We will assume the opposite is true, and find a contradiction. The opposite would be \(A^TA = AA^T\). Suppose A is an \(m\)x\(n\) matrix and \(m \neq n\). Then \(A^T\) would be an \(n\)x\(m\) matrix. \(A^TA\) is t...
3018 sym
605 HW1
HW1 Assignment One of the most useful applications for linear algebra in data science is image manipulation. We often need to compress, expand, warp, skew, etc. images. To do so, we left multiply a transformation matrix by each of the point vectors. For this assignment, build the first letters for both your first and last name using point plots i...
1659 sym 1 img
R HW Week 3
Pizza As with last week, I will use the pizzaplace data set. It is not the most extensive set of data, but sometimes constraints force one to be creative. And often the data you can get your hands on is limited. Therefore this will be a good exercise. Plus, pizza = yum. Quote from reading this week that struck me is: “data analysis … the pr...
6008 sym R (6493 sym/27 pcs) 10 img
R Homework 1
Part 1: 13! first way (for loop) factorialResult<-1 for (i in 2:13) { factorialResult<-i*factorialResult i=i+1 } print(factorialResult) ## [1] 6227020800 Part 1: 13! another way (while loop) factorialResult<-1 i<-1 while (i <=13) { factorialResult<-i*factorialResult i=i+1 } print(factorialResult) ## [1] 6227020800 Part 1: 13...
194 sym R (1051 sym/10 pcs)
R HW week 2
For the questions below, used the pizzaplace data set. Seemed fitting since I am from Brooklyn. Installed chron to use time functions, since pizzaplace has only one numeric field (price), these allow me to take mean and median of the time field. 1. Summary, mean, median 7. Also note that pizzaplace is loaded from my github library(dplyr) ## ##...
2185 sym R (11790 sym/23 pcs)
607 - Week 1
Overview The data set used here is from the article “The (Very) Long Tail of Hurricane Recovery”. https://projects.fivethirtyeight.com/sandy-311/ The article discussed how nearly 5 years after Sandy, 311 was still getting calls from New Yorkers asking for information. The data is pulled from NYC Open Data, and is structured with a row for eac...
2644 sym R (2906 sym/16 pcs) 1 img
D Plunkett 607 Week 7
Introduction: Here we will bring in 3 files: 3Books.html 3Books.xml 3Books.json and compare the results. library(rvest) library(xml2) library(rjson) library(tidyr) First, html html_doc <- html_table(read_html("https://raw.githubusercontent.com/dianaplunkett/607/main/3Books.html")) html_df <- as.data.frame( unlist(html_doc, recursive=FALSE)) ht...
1249 sym R (2075 sym/9 pcs)
D Plunkett 607 Project 1
Overview Load libraries and other set up knitr::opts_chunk$set(echo = TRUE) library(tidyverse) library(magrittr) Load file Chess<- read_delim( "https://raw.githubusercontent.com/dianaplunkett/607/main/tournamentinfo.txt", delim = "|", col_names = FALSE, trim_ws = TRUE, skip = 4, ...
1614 sym R (1760 sym/6 pcs)
D Plunkett 607 Week 3
library(tidyverse) ## ── Attaching packages ─────────────────────────────────────── tidyverse 1.3.1 ── ## ✓ ggplot2 3.3.5 ✓ purrr 0.3.4 ## ✓ tibble 3.1.6 ✓ dplyr 1.0.7 ## ✓ tidyr 1.1.4 ✓ stringr 1.4.0 ## ✓ readr 2.1.2 ✓ f...
2699 sym R (5461 sym/30 pcs)