Correlation & Plotting

This quiz is designed to test and enhance your knowledge of correlation and plotting techniques using Pandas.

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Question 1

What does the .corr() method in Pandas compute by default?

  • Covariance

  • Pearson correlation coefficient

  • Spearman rank correlation

  • Kendall Tau correlation

Question 2

Visualize the correlation matrix for the following DataFrame and interpret the strongest correlation.

Python
import pandas as pd
import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

# Generate data
np.random.seed(42)
df = pd.DataFrame({
    'A': np.random.rand(100),
    'B': np.random.rand(100),
    'C': np.random.rand(100) * 2
})

# Compute and plot correlation
corr_matrix = df.corr()
sns.heatmap(corr_matrix, annot=True, cmap='coolwarm')
plt.title('Correlation Heatmap')
plt.show()


  • Column B and C

  • All are equally correlated

  • Column A and B

  • Column A and C

Question 3

Which type of plot is ideal for analyzing the correlation between two variables?

Python
import pandas as pd
df = pd.DataFrame({
    'A': np.random.rand(50),
    'B': np.random.rand(50)
})

# Plot
plt.scatter(df['A'], df['B'], alpha=0.6)
plt.xlabel('A')
plt.ylabel('B')
plt.title('Scatter Plot of A vs. B')
plt.show()


  • Histogram

  • Boxplot

  • Scatter plot

  • Heatmap

Question 4

Given the following DataFrame, compute and display the pairwise scatter matrix.

Python
import pandas as pd
df = pd.DataFrame({
    'A': [1, 2, 3, 4, 5],
    'B': [10, 9, 8, 7, 6],
    'C': [2, 4, 6, 8, 10]
})

# Pairwise scatter matrix
pd.plotting.scatter_matrix(df, diagonal='hist', figsize=(8, 6))
plt.suptitle("Scatter Matrix")
plt.show()


  • Strong positive correlation between A and C

  • Strong negative correlation between A and B

  • No correlation between B and C

  • Both A and B

Question 5

What does a heatmap with high correlation values look like?

Python
# Generate correlated data
df = pd.DataFrame({
    'X': range(1, 101),
    'Y': [x * 2 for x in range(1, 101)],
    'Z': [x * 3 for x in range(1, 101)]
})

# Heatmap
sns.heatmap(df.corr(), annot=True, cmap='coolwarm')
plt.title('Heatmap of Strong Correlations')
plt.show()


  • A heatmap with values close to 0

  • A heatmap with values close to 1 or -1

  • A mix of positive and negative correlations

  • None of the above

Question 6

Which library can you combine with Pandas for enhanced correlation heatmaps?

  • Matplotlib

  • Seaborn

  • NumPy

  • SciPy


Question 7

What does a correlation coefficient of -1 indicate?

  • No correlation

  • Perfect positive correlation

  • Perfect negative correlation

  • No linear relationship

Question 8

Consider the following DataFrame:

Python
import pandas as pd
df = pd.DataFrame({'A': [1, 2, 3], 'B': [3, 6, 9]})

What is the correlation coefficient between A and B?


  • 0

  • 1

  • -1

  • 0.5

Question 9

What type of plot does the following code generate?

Python
import pandas as pd
df = pd.DataFrame({'A': [1, 2, 3, 4], 'B': [10, 15, 25, 30]})
pd.plotting.scatter_matrix(df)


  • Pair plot

  • Scatter plot

  • Line plot

  • Histogram

Question 10

What does the parameter annot=True do in the Seaborn heatmap function?

  • Displays the correlation values in the heatmap cells

  • Colors the heatmap

  • Normalizes the correlation values

  • Removes axis labels

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