Section 1

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x=matrix(1:6,nrow=2) y=matrix(2:7,nrow=2) z=cbind(x,y) z=rbind(x,y)

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Last updated

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Date created

Mar 1, 2020

Cards (33)

Section 1

(33 cards)

x=matrix(1:6,nrow=2) y=matrix(2:7,nrow=2) z=cbind(x,y) z=rbind(x,y)

Front

- Create a matrix for the sequence 1 through 6, with two rows called x - Create a matrix for the sequence 2 through 7, with two rows called y - Bind the columns of y to x - Bind the rows of y to x

Back

x=3:8 matrix(x,ncol=2)

Front

- Create a sequence from 3 to 8 with increment of 1 - Create matrix with 2 columns, number of rows dependent on the number of values

Back

mn=function(x) {sum(x)/(length(x)-1)} y=1:100 mn(y)

Front

- Define the function and label is mn - Calculate the mean values for the function using a sequence from 1 to 100

Back

data=c(227,8,1.3,1534,58,1.2,2365,82,1.8) country.data=matrix(data, nrow=3, byrow=T)

Front

- Concatenate this string of values and call it data - Convert it to a matrix named country.data with 3 rows, filling by the row instead of column

Back

dimnames(country.data)=list(countries,variables)

Front

- Assign the previously created row and column names to the data -First list value is row name, second is column name

Back

rep(3,5)

Front

- Create a matrix of value 3, repeated 5 times 3 3 3 3 3

Back

dimnames(country.data)

Front

- Show dimension names

Back

variables=c("GDP", "POP", "Inflation")

Front

- List of column names for GDP, population, and inflation

Back

x=seq(1,20,5) x>7 indx=x>10

Front

- Create sequence 1 to 20 in increments of 5 - True/False statements for values greater than 7 for the sequence -

Back

country.data[2,3]

Front

- What is the value of the second row and the third column?

Back

x=3:8 matrix(x)

Front

- Create a sequence from 3 to 8 with increment of 1 - Create matrix of sequence (one column)

Back

x=rnorm(100) plot(x,pnorm(x)) plot(x,dnorm(x))

Front

- Generate 100 random numbers - Plot the distribution function - Plot the density function

Back

country.data[2,] country.data[,2]

Front

- Show all data in row 2 - Show all data in column 2

Back

country.data[1,2]=10

Front

- Replace the value in the first row and second column with 10

Back

for (i in 1:1000) y=c(y,mean(rnorm(100))) hist(y)

Front

- Generate 100 random numbers and calculate the mean, 1000 times - Plot the histogram

Back

x=seq(-5,25,length.out=50)

Front

- Sequence from -5 to 25 with 50 uniform increments

Back

rep(c(1,2,3),2)

Front

- Concatenate values 1, 2, and 3, and repeat it twice 1 2 3 1 2 3

Back

rowMeans(country.data)

Front

- Calculate the mean for each row of data

Back

x=1:10 y=2:11 x+y x*y x %% y

Front

- Create sequence called x from 1 to 10 in increments of 1 - Create sequence called y from 2 to 11 in increments of 1 - Add all matching x and y elements - Multiply all matching x and y elements - Multiply the two elements using matrix math (dot product)

Back

x=-5:25

Front

- Same thing, creates sequence -5 to 25 in increments of 1

Back

x<-c(1,20,5) x[x>10] sum(x[x>10])

Front

- Create sequence 1 to 20 in increments of 5 - Select elements of x greater than 10 - Add up elements of x greater than 10

Back

x=seq(-5,25,2)

Front

- Sequence from -5 to 25 in increments of 2

Back

x=3:8 matrix(c,ncol=3,byrow=T)

Front

- Create a sequence from 3 to 8 with increment of 1 - Create a matrix with 3 columns, with sequence increasing by row and not by columns

Back

colMeans(country.data)

Front

- Calculate the mean for each column of data

Back

EU=c("EU","EU","Non-EU") country.frame=data.frame(country,data,EU)

Front

- Create a list of character strings - Add the list to the data frame

Back

x=3:8 matrix(x,3,2)

Front

- Create a sequence from 3 to 8 with increment of 1 - Create matrix with 3 rows and 2 columns

Back

x=c(1,3,5)

Front

Creates matrix: x = 1 3 5

Back

x=1:10 y=20:30 z=c(x,y)

Front

- Create sequence called x from 1 to 10 in increments of 1 - Create sequence called y from 20 to 30 in increments of 1 - Concatenate the two into a sequence called z

Back

apply(country.data,2,max)

Front

- Compute the maximum values in each column

Back

countries=c("austria", "france", "germany")

Front

- Create a list of row names for Austria, France, and Germany

Back

mean(rnorm(100))

Front

- Calculate the mean of a random 100 numbers

Back

dim(country.data)

Front

- What are the dimensions of the data?

Back

x=seq(-5,25)

Front

- Sequence from -5 to 25, with increment of 1

Back