R Programming Language Multiple Choice Questions on “Visualizing Data ”.
1. Which of the following adds marginal sums to an existing table?
a) par()
b) prop.table()
c) addmargins()
d) quantile()
Answer: b
Clarification: prop.table() computes proportions from a contingency table.
2. Which of the following lists names of variables in a data.frame?
a) quantile()
b) names()
c) barchart()
d) par()
Answer: a
Clarification: names function is used to associate name with the value in the vector.
3. Which of the following is tool for chi-square distributions?
a) pchisq()
b) chisq()
c) pnorm
d) barchart()
Answer: c
Clarification: pnorm() is tool for normal distributions.
4. Which of the following groups values of a variable into larger bins?
a) cut
b) col.max(x)
c) stem
d) which.max(x)
Answer: a
Clarification: stem() is used to make a stemplot.
5. Which of the following determine the least-squares regression line?
a) histo()
b) lm
c) barlm()
d) col.max(x)
Answer: b
Clarification: lm calls the lower level functions lm.fit.
6. Which of the following is tool for checking normality?
a) qqline()
b) qline()
c) anova()
d) lm()
Answer: a
Clarification: qqnorm is another tool for checking normality.
7. Which of the following is lattice command for producing boxplots?
a) plot()
b) bwplot()
c) xyplot()
d) barlm()
Answer: b
Clarification: The function bwplot() makes box-and-whisker plots for numerical variables.
8. Which of the following compute analysis of variance table for fitted model?
a) ecdf()
b) cum()
c) anova()
d) bwplot()
Answer: c
Clarification: ecdf() builds empirical cumulative distribution function.
9. Which of the following is used to find variance of all values?
a) var()
b) sd()
c) mean()
d) anova()
Answer: a
Clarification: sd() is used to calculate standard deviation.
10.The purpose of fisher.test() is _______ test for contingency table.
a) Chisq
b) Fisher
c) Prop
d) Stem
Answer: b
Clarification: prop.test() is used to inference for 1 proportion using normal approx.