1. Question 1

What Python library is primarily used for machine learning?

• ❌ pandas

• ❌ Numpy

• ❌ matplotlib

• ✅ scikit-learn

Explanation:
Scikit-learn is Python’s main machine-learning library (classification, regression, clustering).

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2. Question 2

Replace column headers of DataFrame df:

• ❌ df.tail() = headers_list

• ✅ df.columns = headers_list

• ❌ df.tail(headers_list)

• ❌ df.head(headers_list)

Explanation:
Assigning to df.columns updates all column names.

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3. Question 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() reads CSV files into Pandas.

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4. Question 4

Most appropriate data type for numeric cylinders (4, 6, 8):

• ❌ float64

• ❌ string

• ✅ int64

• ❌ object

Explanation:
The values are whole numbers → integer type.

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5. Question 5

Show descriptive statistics for all columns including text:

• ❌ df.info()

• ✅ df.describe(include = “all”)

• ❌ df.summary(include=”all”)

• ❌ df.describe()

Explanation:
include="all" forces describe() to include numeric + object columns.

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6. Question 6

‘price’ is meant to be predicted → it is the:

• ❌ Independent variable

• ❌ Categorical variable

• ✅ Target variable

• ❌ Index variable

Explanation:
The variable being predicted is always the target.

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7. Question 7

Role of sqlite3.connect():

• ❌ Exports CSV

• ✅ Opens a connection to the database file

• ❌ Fetches query results

• ❌ Defines SQL query

Explanation:
connect() establishes DB access.

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8. Question 8

Best library to visualize trends in used car prices:

• ❌ Numpy

• ❌ Pandas

• ❌ Scikit-learn

• ✅ Matplotlib

Explanation:
Matplotlib is the primary visualization library.

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9. Question 9

Assign custom header list to DataFrame:

• ❌ headers = df.columns()

• ❌ rename.columns(df, headers)

• ❌ df.labels = headers

• ✅ df.columns = headers

Explanation:
df.columns is directly assignable.

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10. Question 10

First step after importing sqlite3:

• ❌ Define cursor()

• ✅ Use connect() to establish connection

• ❌ Run execute() directly

• ❌ fetchall()

Explanation:
You must connect before running any SQL.

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🧾 Summary Table

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