Publications by Songqi Cheng
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Issue Summary What is Heteroskedasticity Heteroskedasticity means that the variability of errors in a regression model is different across observations. This can lead to incorrect estimates of the standard errors of the regression coefficients and affect hypothesis testing. In simpler terms, it means that the variability in the data is not constan...
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MoneyBall Assignment
MoneyBall Assignment Data Exploration In this assignment, we will be analyzing approximately 2200 records from year of 1871 to 2006, Each record has the performance of the team for the given year, with all of the statistics adjusted to match the performance of a 162 game season. Firstly, import the data and load required packages to perform gener...
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Week 4 discussion
GDP SERIES # “A191RC” library(bea.R) ## Loading required package: data.table ## Creating a generic function for 'toJSON' from package 'jsonlite' in package 'googleVis' ## Note: As of February 2018, beaGet() requires 'TableName' for NIPA and NIUnderlyingDetail data instead of 'TableID.' See https://github.us-bea/bea.R for details. library(tidyve...
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Homework 3 distribution
rm(list = ls()) Question1 n <- 20 p <- 0.5 prob <- sum(dbinom(9:12, size=n, prob=p)) prob ## [1] 0.6166897 The probability of 9 to 12 buyers prefer red is 0.6167 Question 2 n<- 13 x<- 0.8 pi<- .2 binom<-dbinom(0:n, n, pi) sum(binom[5:6]) ## [1] 0.2226404 The probability of less than 6 but more than 3 bulbs from the sample are defective is 0.222...
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Homework Week 2 probability
Question 1 my.dice.sum <- function (n.side){ dice <- sample(1:n.sides, size=n.dice, replace = TRUE) return(sum(dice)) } s <- 6 n <- 3 probability <- (1/s)^n print(probability) ## [1] 0.00462963 The probability of rolling a dice three times and get a sum of 12 is 0.00463 Question 2 maleother <- 200 femaleother <- 100 total <- 1700 prob <- (ma...
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test
1 Official R Markdown Guide The link above is what you should explore to understand R Markdown. Can replace ‘html_document’ with ‘pdf_document’ in the .Rmd (Rmarkdown) file above manually to generate the output in your preferred format. However, I would strongly suggest using HTML format initially as the setup is likely to reduce math sym...
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