6  Sample of Questions

6.1 Sample 1

Introduction

In this exercise, we will perform Exploratory Data Analysis (EDA) using the penguins dataset from the palmerpenguins package.

At each step, you will find a question to test your understanding.

Step 1: First Look

The dataset has 344 rows and 8 variables. Some values are missing.

Question 1. How many variables are categorical?

  1. 2
  2. 3
  3. 4
  4. 5

Correct Answer: B

Step 2. Numerical Summaries

The body mass ranges from about 2700g to 6300g.

Question 2. Which measure is most robust to outliers?

  1. Mean
  2. Standard deviation
  3. Interquartile Range (IQR)
  4. Variance

Correct Answer: C

Step 3: Visualization – Boxplot

Gentoo penguins appear heavier than Adelie and Chinstrap.

Question 3. What does each box in the boxplot represent?

  1. The entire dataset    
  2. Distribution of body mass for one species
  3. Only the mean of each species    
  4. Outliers only

Correct Answer: C

Step 4: Relationships Between Variables

Flipper length and body mass are positively related.

Question 4. What does a positive relationship mean here?

  1. Larger flipper length tends to go with higher body mass

  2. Flipper length causes body mass

  3. There is no association

  4. Outliers explain the pattern

Correct Answer: A

Step 5: Missing Data

The variable sex has missing values.

Question 5. Which R function checks if any missing values exist in the dataset?

  1. is.na()
  2. anyNA()
  3. all()
  4. na.rm()

Correct Answer: B

6.2 Sample 2

we will explore the mtcars dataset, which contains fuel consumption and performance information about \(32\) car models from 1974.

We will perform EDA and answer questions along the way.

Step 1. First Look

The dataset has \(32\) observations and \(11\) variables.

Question 1. How many variables are numeric?

  1. 8
  2. 9
  3. 10
  4. 11

Correct Answer: B

Step 2: Descriptive Statistics

The miles-per-gallon (mpg) ranges from \(10.4\) to \(33.9\).

Question 2. Which value best describes the typical mpg while being robust to outliers?

  1. \(20.9\)
  2. \(19.20\)  
  3. \(7.375\)   
  4. \(6.026948\)

Correct Answer: B

Step 3: Categorical Variable – Cylinders

Cars come with \(4\), \(6\), or \(8\) cylinders.

Question 3. Which cylinder type is most common in the dataset?

  1. 4 cylinders
  2. 6 cylinders
  3. 8 cylinders
  4. All equally common

Step 4: Visualization – Boxplot

Question 4. What does the plot suggest?

  1. Cars with more cylinders have higher mpg
  2. Cars with more cylinders have lower mpg
  3. Cars with more cylinders have identical mpg
  4. No relationship is visible

Correct Answer: B

Step 5: Relationship Between Variables

Question 5. What trend do we see between horsepower (hp) and miles per gallon (mpg)?

  1. Higher horsepower cars tend to have lower mpg
  2. Higher horsepower cars tend to have higher mpg
  3. No relationship
  4. Only automatic cars follow this trend

Correct Answer: A

Step 6: Correlation

Question 6. What does the correlation between hp and mpg mean?

  1. Strong positive relationship
  2. Strong negative relationship
  3. Weak negative relationship
  4. No relationship

Correct Answer: B