Publications by sufian
DAT 605 - Discussion 11
require(ggthemes) library(tidyverse) library(magrittr) library(tidyr) library(dplyr) library(lubridate) library(ggplot2) library(fpp2) library(forecast) library(ggpubr) library(boot) A Simple Linear Regression Model Here is an example of a statistical relationship. The response variable y is the mortality due to skin cancer (number...
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Dat 605 - ASSIGNMENT 11
For the linear regression line to be useful for predictive purposes, certain conditions must hold: 1) The samples which we used to fit the line must be independent. 2) The relationship between the descriptive and response variables must be linear. 3) The residuals from the regression line must be nearly normal. 4) The variability of our obse...
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Payroll Forecasting - FP&A
The Objective of this exercise is to determine if regression or any other time series models are suitable for forecasting the FP&A payroll data sets. Gross Payroll is used as a test case and the following models (in Ascending Order) of complexity were utilized to show case its efficacy: - Excel's Linear Regression Model - Excel's Exponenti...
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DAT 605 - Discussion 10
Intro to Probabilities page 451 Chapter 11.4 Exercise 1 Compute Py, P2y, and P4y and show that the results are approaching a constant vector. What is this vector? ans: The vector approaches {0.33,0.33} library(matlib) library(MASS) p<- matrix(c(0.5, 0.5, 0.25, 0.75), nrow = 2, ncol = 2, byrow=T) p ## [,1] [,2] ## [1,] 0.50 0.50 ## [2...
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DAT 605 - Discussion 9
“Intro to Prob” Page 338 Prob1: Let S100 be the number of heads that turn up in 100 tosses of a fair coin. Use the Central Limit Theorem to estimate the following conditions: From chpter 9, CLT page 332: normal density between standardized values are: i-1/2 => (i-1/2-np)/sqrt(npq), lower bound j-1/2 => (j+1/2-np)/sqrt(npq), upper bound exerc...
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DAT 605 - ASSIGNMENT 9
Prob 11 Page 363 from “Intro to Probability Book” Given that Xn = Yn+1 - Yn And that \(\mu\) = 0, \(\sigma\) = 1/2 and Y1 = 100 In 365 days, Yn+1={100,Y2,Y3,….,Y365} and Xn+1 - Xn is (Yn+2-Yn+1) - (Yn+1 - Yn) … => Yn+2 - Yn …. Therefore, Sum of 365 days of price differentials: S365=(Y2−100)+(Y3−Y2)+(Y4−Y3)+….+(Y365−Y364) which...
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DAT 605 - Discussion 6, 2nd post
Intro to Proability Chp 4.1 DISCRETE CONDITIONAL PROBABILITY page: 156 Prob 1 For a fair die that was rolled twice: $ R^2$ with R ={1,2,3,4,5,6} and the common distribution function is 1/6 for all possible outcomes Given that X = min(X1,X2) where X1 is one outcome and X2 is the other possible outcome Also let F(x) be the CDF: F(x) = P(X≤x) =...
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DAT 605 - ASSIGNMENT 7
Types of Probability Distribution Exercise library(matlib) library(MASS) Prob 1 Let Y = min(X1,X2,X3,X4….Xn) Also let F(y) be the CDF: F(y) = P(Y≤y) = 1 - P(Y<y) = 1 - P(X1>y, X2>y, X3>y,...........Xn>y) = 1 - P(X1>y)*P(X2>y)*P(X3>y)....*P(Xn>y) = 1 - F(x1)*F(x2)*F(x3)*...........*F(xn) Therefore, F(y) = 1 - [\(\frac{1}{k}\)\(\f...
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DAT 605 - ASSIGNMENT 6
HW 6 library(matlib) library(MASS) require(plotrix) require(grid) library(ggplot2) require(ggthemes) require(combinat) Prob 1 red_marbles <- 54 white_marbles <- 9 blue_marbles <- 75 Tot_marbles <- red_marbles+white_marbles+blue_marbles Pred <- round(red_marbles/Tot_marbles,4) #probability of pulling red marble Pblue <- round(blue...
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DAT 605 - ASSIGNMENT 5
HW5 library(matlib) library(MASS) require(plotrix) require(grid) library(ggplot2) require(ggthemes) 5a Find probability of B+C < 1/2 B + C < 1/2 passes through the points (1/2, 0) and (0, 1/2) Solving by geometry: The probability is therefore the area under the line of b= 1/2 - C ans: 1/21/21/2 = 1/8 curve(0.5-x, from=0.0, to=0.5, , xla...
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