MGSC 291 Exam 1 University of South Carolina
Questions and Answers 2024-2025
putting in a dataset - Correct Ans-data<-
c(81,85,93,93,99,76,75,84,78,84,81,82,89,81,96,82,74,70,84,86,80,70,131,75,88,102,1
15,89,82,79,106)
length(data) - Correct Ans-tells you how may entries are in your vector
sort(data) - Correct Ans-puts data smallest to largest
summary(data) - Correct Ans-returns the five number summary and the sample mean
mean(data)
sd(data)
sum(data) - Correct Ans-sample mean
sample standard deviation
adds all the elements of the vector
seq(1,100,1)
seq(2,100,2) - Correct Ans-tells r to create the sequence of numbers from 1 to 100 by 1
(1,2,3...)
1:100 does the same thing
(2,4,6...100)
data<-read.table(file.choose(),header=TRUE)
read.cvs - Correct Ans-calls this dataset into r and you can name it whatever you want
getwd() - Correct Ans-creates the current working directory and calls in your data too
dim(data) - Correct Ans-checks dimensions of data
data - Correct Ans-type the name of the data to see it
data[1:5] - Correct Ans-calls in the first five rows of the dataset if you are working with a
large dataset
head(data) - Correct Ans-shows the first few rows
data[,1:2] - Correct Ans-all rows for columns 1 and 2
data[1:5,1:2] - Correct Ans-first five rows and first two columns
str(data) - Correct Ans-structure of the object
, View(data) - Correct Ans-(capital V) puts your data in a viewable popup window
data$shoes - Correct Ans-calls in the column called shoes
attach(data) - Correct Ans-attaches data so you can work with it and don't have to keep
calling it in
(if you attach several datasets that have the same column names r will be confused so
you have to detach before attaching again)
data<-subset(data,Type=="WT") - Correct Ans-you can pick out certain rows/columns
and you can enter more == and "" in order to be more specific
hist(data) - Correct Ans-give you a histogram
hist(data,breaks=c(60,70,80,90)) - Correct Ans-creates a sequence and breaks them
xlab="percents of ..." - Correct Ans-x axis name
ylab="Frequency" - Correct Ans-y axis name
main="..." - Correct Ans-title of the graph
boxplot(data) - Correct Ans-gives a box plot
boxplot(...~...) - Correct Ans-gives side by side boxplots
boxplot(Oil~Type,names=c("WIld Type","Mutated")) - Correct Ans-creates your own
label for the boxplot
plot(X,Y) - Correct Ans-create a scatterplot
X1 <- c(8,5,14,13,29)
X2 <- c(13,8,6,18,4) - Correct Ans-X1 is first line with the numbers you want
X2...
dbinom(j,n,p) - Correct Ans-gives P(Y = j) discrete binomial probability
pbinom(J,n,p) - Correct Ans-gives P(<=J) = P(Y = 0) + P(Y = 1) + ... + P(Y = J) exp
binomial prob
dpois(j,lambda) - Correct Ans-gives P(X=j) poisson discrete
ppois(J,lambda) - Correct Ans-gives P(X<=J) poisson exponential
pexp(x,lambda) - Correct Ans-gives P(Y<=j) exponential
