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Graded Quiz: Exploratory Data Analysis :Data Analysis with Python (IBM Data Analyst Professional Certificate) Answers 2025

1. Question 1

Elina wants summary statistics (count, mean, std). What should she use?

  • ❌ head()

  • ❌ tail()

  • ✅ describe()

  • ❌ summary()

Explanation:

df.describe() gives summary statistics for numerical columns.


2. Question 2

Pearson correlation close to zero means:

  • ❌ Mean of data near zero

  • ❌ Uncertainty between variables

  • ❌ Minimal deviation

  • ✅ Two variables are not correlated

Explanation:

Correlation ≈ 0 → no linear relationship.


3. Question 3

Reshape data so one variable becomes rows and another becomes columns:

  • ❌ merge()

  • ❌ groupby()

  • ✅ pivot()

  • ❌ pcolor()

Explanation:

pivot() reshapes long data → wide format with rows vs columns.


4. Question 4

Result of:

df_grp = df_test.groupby(['body-style'], as_index=False).mean()
df_grp['price']
  • ❌ Averages body-style variable

  • ❌ Writes mean value of each body-style price to the dataframe (wording unclear)

  • ❌ Averages price for all body labels

  • ✅ It averages the price for each body style.

Explanation:

Groupby + mean computes mean price for each body-style category.


5. Question 5

No clear trend between peak RPM and price means:

  • ✅ Weak or no correlation

  • ❌ Strong negative

  • ❌ Uncertain

  • ❌ Strong positive

Explanation:

Scattered values without trend → very low correlation.


🧾 Summary Table

Q Correct Answer Key Concept
1 describe() Summary statistics
2 Variables not correlated Pearson ≈ 0
3 pivot() Data reshaping
4 Mean price per body-style groupby + mean
5 Weak/no correlation Relationship analysis