Data Science with Python Certification Data Science with Python Exploratory Data Analysis 4

Question 1

Which pandas method is used to compute pairwise correlations between all numeric columns of a DataFrame?

Accepted Answer

df.corr()

Answer

df.corr() computes pairwise Pearson (or other) correlation coefficients between all numeric columns and returns a correlation matrix.

Question 2

In a heatmap created with seaborn's sns.heatmap(), what does the annot=True parameter do?

Accepted Answer

Annotates each cell with its numeric value

Answer

annot=True prints the data value inside each cell of the heatmap for easy reading.

Question 3

What is the purpose of using pd.cut() during EDA?

Accepted Answer

To bin a continuous variable into discrete intervals

Answer

pd.cut() segments and sorts data values into discrete bins, converting a continuous variable into an ordinal categorical one.

Question 4

Which of the following correctly identifies a bimodal distribution in a histogram?

Accepted Answer

Two distinct peaks in the frequency distribution

Answer

A bimodal distribution has two local maxima (peaks), suggesting the data may come from two different subpopulations.

Question 5

When using matplotlib's plt.subplots(2, 3), what is the shape of the returned axes object?

Accepted Answer

A 2D NumPy array of shape (2, 3)

Answer

plt.subplots(nrows, ncols) returns a Figure and a 2D array of Axes objects with shape (nrows, ncols).

Data Science with Python Certification Practice Test