Data Analytics Week 5 Quiz

What does the tapply function do in R?

• • Applies a function over subsets of a vector

• • Applies a function over a data frame

• • Applies a function to each element of a vector

• • Applies a function to each column of a data frame

What does the ifelse function return?

• • A matrix

• • A vector of the same length as the test

• • A data frame

• • A list

What is the main purpose of a two-sample t-test?

• • To compare two proportions

• • To compare the variances of two groups

• • To compare the means of two groups

• • To compare the medians of two groups

What is a pairwise comparison?

• • Comparing each pair of data points in a single dataset

• • Comparing each pair of variances from multiple groups

• • Comparing each pair of medians from multiple groups

• • Comparing each pair of means from multiple groups

What is the main objective of simple linear regression?

• • To find the correlation between two variables

• • To model the relationship between a single predictor and a response variable

• • To predict the response variable using multiple predictors

• • To classify data into categories

What is the purpose of a two-way ANOVA?

• • To compare the means of two groups

• • To analyze the correlation between two variables

• • To assess the interaction between two factors

• • To test the variance of a single factor

Which function in R can be used to add a trend line to a scatterplot?

• • abline()

• • lm()

• • trendline()

• • lines()

What is multiple linear regression used for?

• • To model the relationship between one predictor and one response variable

• • To classify data into categories

• • To perform clustering analysis

• • To model the relationship between multiple predictors and a single response variable

What is the purpose of descriptive statistics in R Studio?

• To manipulate and transform data in R Studio.

• To create visualizations and plots in R Studio.

• To perform advanced statistical analysis in R Studio.

• To summarize and describe the main features of a dataset.

When graphing data on a bar graph, what does the height of each bar represent?

• The category of the data

• The frequency of each category

• The total number of data points

• The average value of the data