Graded Quiz: Importing Data Sets:Data Analysis with Python (Applied Data Science Specialization) Answers 2025

1. What Python library is primarily used for machine learning?

• ❌ pandas

• ❌ Numpy

• ❌ matplotlib

• ✅ scikit-learn

Explanation: scikit-learn is the standard library for machine learning algorithms in Python.

2. Which command correctly replaces the column headers of a DataFrame?

• ❌ df.tail() = headers_list

• ✅ df.columns = headers_list

• ❌ df.tail(headers_list)

• ❌ df.head(headers_list)

Explanation: df.columns holds the list of column names and can be reassigned directly.

3. Load “A.csv” into a DataFrame

• ❌ df.tail(“A.csv”)

• ✅ df = pandas.read_csv(“A.csv”)

• ❌ df.columns = “A.csv”

• ❌ pandas.load_data(“A.csv”)

Explanation: read_csv() is the correct function to import CSV files.

4. Best data type for cylinders (4, 6, 8)

• ❌ float64

• ❌ string

• ✅ int64

• ❌ object

Explanation: Cylinder values are whole numbers; integer type is most suitable.

5. Which shows descriptive stats for all columns?

• ❌ df.info()

• ✅ df.describe(include = “all”)

• ❌ df.summary(include = “all”)

• ❌ df.describe()

Explanation: include="all" ensures both numeric & object columns are included.

6. What type of variable is ‘price’?

• ❌ Independent variable

• ❌ Categorical variable

• ✅ Target variable

• ❌ Index variable

Explanation: Price is the output you want to predict → target/dependent variable.

7. Role of sqlite3.connect()?

• ❌ It exports the data to CSV

• ✅ It opens a connection to the specified database file

• ❌ It fetches query results

• ❌ It defines the SQL query

Explanation: connect() establishes a link between Python and the database.

8. Best library for visualizing trends?

• ❌ Numpy

• ❌ Pandas

• ❌ Scikit-learn

• ✅ Matplotlib

Explanation: Matplotlib is used for plotting and data visualization.

9. Assign a custom header list to DataFrame

• ❌ headers = df.columns()

• ❌ rename.columns(df, headers)

• ❌ df.labels = headers

• ✅ df.columns = headers

Explanation: df.columns is directly assigned a new list of headers.

10. First step after importing sqlite3

• ❌ Define cursor() directly

• ✅ Use connect() to establish connection

• ❌ Run SQL using execute()

• ❌ Apply fetchall()

Explanation: You must connect to the database before creating a cursor or executing queries.

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