Publications by CHUNJIE NAN
Who is Drunk in Ames, Iowa
1. Breath alcohol tests in Ames, Iowa, USA Ames, Iowa, USA is the home of Iowa State University, a land grant university with over 36,000 students. By comparison, the city of Ames, Iowa, itself only has about 65,000 residents. As with any other college town, Ames has had its fair share of alcohol-related incidents. (For example, Google ‘VEISHEA...
3794 sym R (7969 sym/35 pcs) 5 img
DATA605_week2_discussion
T21. Suppose that V is a vector space, and u, v, w \(\in\) V. if w + u = w + v, then u = v. u + w = v + w (u + w) + (-w) = (v + w) + (-w) u + (w + (-w)) = v + (w + (-w)) u + 0 = v + 0 u = v ...
100 sym R (133 sym/1 pcs)
DATA605_week1_discussion
SLE C33 x + y - z = -1 x - y - z = -1 z = 2 a <- matrix(c(1, 1, 0, 1, -1, 0, -1, -1, 1), nrow=3) a ## [,1] [,2] [,3] ## [1,] 1 1 -1 ## [2,] 1 -1 -1 ## [3,] 0 0 1 b <- matrix(c(-1, -1, 2), nrow=3) b ## [,1] ## [1,] -1 ## [2,] -1 ## [3,] 2 solve(a,b) ## [,1] ## [1,] 1 ## [2,] 0 ## [3,] 2 There...
89 sym R (293 sym/6 pcs)
DATA605_HW1_ChunjieNan
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 in R. For exampl...
1068 sym R (3859 sym/18 pcs) 5 img
DATA608_Chunjie_Nan_Module1_HW1
Principles of Data Visualization and Introduction to ggplot2 I have provided you with data about the 5,000 fastest growing companies in the US, as compiled by Inc. magazine. lets read this in: inc <- read.csv("https://raw.githubusercontent.com/charleyferrari/CUNY_DATA_608/master/module1/Data/inc5000_data.csv", header= TRUE) And lets preview this...
2852 sym R (5967 sym/25 pcs) 4 img
DATA605_HW2_ChunjieNan
Problem Set 1. Show that \(A^TA \ne AA^T\)in general. (Proof and demonstration.) For a special type of square matrix A, we get \(A^T A = AA^T\). Under what conditions could this be true? (Hint: The Identity matrix I is an example of such a matrix). Please typeset your response using LaTeX mode in RStudio. If you do it in paper, please either sca...
2579 sym R (3871 sym/43 pcs)
DATA622_HW2_ChunjieNan
0.0.1 Project Overview Based on the latest topics presented, bring a dataset of your choice and create a Decision Tree where you can solve a classification or regression problem and predict the outcome of a particular feature or detail of the data used. Switch variables to generate 2 decision trees and compare the results. Create a random forest...
15779 sym R (5344 sym/43 pcs) 6 img 3 tbl
DATA605_HW9_ChunjieNan
9.3.11 The price of one share of stock in the Pilsdorff Beer Company (see Exercise 8.2.12) is given by Yn on the nth day of the year. Finn observes that the differences Xn = Yn+1 − Yn appear to be independent random variables with a common distribution having mean \(\mu\) = 0 and variance \(\delta2\) = 1/4. If Y1 = 100, estimate the probabil...
1711 sym R (198 sym/7 pcs)
DATA622_HW1_ChunjieNan
Visit the following website and explore the range of sizes of this dataset (from 100 to 5 million records).https://eforexcel.com/wp/downloads-18-sample-csv-files-data-sets-for-testing-sales/ Based on your computer’s capabilities (memory, CPU), select 2 files you can handle (recommended one small, one large) Review the structure and content of t...
18556 sym R (19616 sym/73 pcs) 6 img
DATA605_HW7_ChunjieNan
1. Let X1, X2, . . . , Xn be n mutually independent random variables, each of which is uniformly distributed on the integers from 1 to k. Let Y denote the minimum of the Xi’s. Find the distribution of Y . We have X1, X2, … to Xn, then total number of possibilities = kn The possibilities none of Xi equals to 1 is (k-1)^n When X = 1 \[P(X=1) = ...
1762 sym R (663 sym/27 pcs)