R Programming Practice Test 8

1. ______ splits a data frame and results an array (hence the da). Hopefully you're getting the idea here.

apply

daply

stats

plyr

2. __________ produces bivariate scatterplots or time-series plots.

bwplot

dotplot

xyplot

barchart

3. Which of the following is true about the base plotting system?

Plots are typically created with a single function call

Margins and spacings are adjusted automatically depending on the type of plot and the data

The system is most useful for conditioning plots

Plots are created and annotated with separate functions

4. Which function opens the screen graphics device for the Mac?

quartz()

png()

pdf()

bitmap()

5. which of the following statement tells the row with the minimum value for every column?

z=apply(x,1,which.min)

z=apply(1,1,which.max)

which.max(x)

which.min(x)

6. Which of the following functions is typically used to add elements to a plot in the base graphics system?

boxplot()

plot()

lines()

hist()

7. ________ add new variables/columns or transform existing variables.

add

apped

arrange

mutate

8. ______ let's you perform SQL queries on your R data frames.

plyr

forecast

sqldf

daply

9. Spread function is known as ___________ in spreadsheets.

pivot

order

unpivot

cast

10. __________ is used when you have variables that form rows instead of columns.

gather()

spread()

tidy()

separate()