Page 247 - Data Science class 11
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6. Many quantitative analysts use R as their ______________________ tool.
a. Leading tool b. Programming tool
c. Both a and b d. None of these
7. Descriptive analysis tells us about ______________________.
a. Past b. Present
c. Future d. All of these
8. Which of the following sorts the dataframe by the order of the elements in B?
a. x[rev(order(x$B)),] b. x[ordersort(x$B),]
c. x[order(x$B),] d. None of these
9 A matrix is ______________________dimensionsinal rectangular data set.
a. 5 b. 4
c. 3 d. 2
10. The ______________________ function takes a vector or other object and splits it into groups determined by a factor or list
of factors.
a. apply() b. split()
c. isplit() d. mapply()
11. ______________________ applies a function over the margins of an array.
a. apply() b. lapply()
c. tapply() d. mapply()
12. Data frames can be converted to a matrix by calling data ______________________.
a. matr() b. mat()
c. matrix() d. None of these
13. Which of the following methods makes a vector of repeated values?
a. rep() b. data()
c. view() d. None of these
14. R objects can have attributes that are like ______________________ for the object.
a. metadata b. features
c. expressions d. All of these
15. Attributes of an object (if any) can be accessed using the ______________________ function.
a. objects() b. attrib()
c. attributes() d. All of these
16. ______________________ involves predicting a response with meaningful magnitude, such as quantity sold, stock price, or
return on investment.
a. Regression b. Clustering
c. Summarization d. None of these
17. ______________________ provides needed string operators in R.
a. str b. forcast
c. stringr d. None of these
Programming with R 245

