BDM300 Week 2

What function can be used to ONLY obtain the number of rows and columns in a dataset in R?

Dim()

Names()

Str()

Attributes()

If you want to view ONLY the column names of a dataset in R, which function should you use?

Columns()

Names()

Str()

Attributes()

Which function in R provides quantitative measures like minimum, maximum, quartiles, and mean for numeric variables and frequencies for categorical?

Describe()

Collection()

Str()

Summary()

How can you display the first 3 rows of a dataset named df in R?

Df[0:3, ]

Head(df, 3)

Df$Sepal.Length[0:3]

Df[3]

If you want to visualize the distribution of two numeric variables in R, which type of plot would you use?

Bar plot

Pie chart

Scatterplot

Frequency Table

What R function is used to calculate the correlation between two numeric variables?

Correlation()

Cor()

Var()

Correl()

In R, what does a correlation value of -1 indicate between two variables?

No relationship

Strong positive relationship

Strong negative relationship

Weak positive relationship

What is the difference between covariance and correlation in R?

Covariance is unbounded, while correlation is bounded between -1 and 1.

Covariance measures the strength and direction of a relationship, while correlation does not.

Correlation measures the strength and direction of a linear relationship, while covariance does not specify the strength or direction.

Covariance is a standardized measure, while correlation is not standardized.

If you want to create a frequency table for a categorical variable in R, which function should you use?

Crosstab()

Table()

Value_counts()

Frequency()

In R, what does the attributes() function return about a dataset that the str() function does not?

Number of rows and columns

Data type of the dataset

Row names

Data summary statistics

What is the primary difference between using df[1:10, "Sepal.Length"] and df$Sepal.Length[1:10] to extract data in R?

The first method extracts the first 10 rows of a dataframe called df, and the second method extracts the first 10 rows of a dataframe called df$Sepal.Length

The first method runs faster than the second method.

Both methods extract the same data.

The first method is used for numeric columns, and the second method is used for factor columns.

When using the summary() function, what does it display for each unique value in a categorical variable?

Quartile values

Mean and median

Frequency count

Variance

If you want to visualize the relationships between multiple variables in R, which of the following functions should you use?

Cor()

Var()

Rel()

Lm()

What information does the range() function provide about a numeric variable in R?

The minimum and maximum values

The quartiles

The mean and median

The standard deviation

When creating a pie chart in R to visualize a categorical variable, which function is essential before using the pie() function?

Range()

Table()

Plot()

Fit()

What does the "0th percentile" represent when using the quantile() function in R?

The minimum value

The mean

The maximum value

The median

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