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This quiz was administered in-person. Students were allowed a double-sided sheet of handwritten notes. Students had 20 minutes to work on the quiz.

This quiz covered Lectures 7-11 of the Winter 2025 offering of DSC 10.

Note (groupby / pandas 2.0): Pandas 2.0+ no longer silently drops columns that can’t be aggregated after a groupby, so code written for older pandas may behave differently or raise errors. In these practice materials we use .get() to select the column(s) we want after .groupby(...).mean() (or other aggregations) so that our solutions run on current pandas. On real exams you will not be penalized for omitting .get() when the old behavior would have produced the same answer.

The DataFrame blue_bowl contains information about orders placed by UCSD students at Blue Bowl, an on-campus eatery specializing in custom bowls. For each order, we have the customer’s "student_id", the "base" of their bowl, which "fruit" they got, and the number of additional toppings, "num_toppings". The first five rows are shown below.

Problem 1

Fill in the blanks so that the statement below outputs a DataFrame showing the most popular base and fruit combinations in the blue_bowl DataFrame, in descending order of popularity.

    blue_bowl.groupby(__(a)__).__(b)__.sort_values(__(c)__)

Problem 2

Let five_bowls be the smaller DataFrame consisting of only the first five rows of blue_bowl.

Problem 2.1

How many rows are in the DataFrame five_bowls.merge(five_bowls, on="base")?

• 5

• 9

• 11

• 15

• 25

• None of these

Problem 2.2

How many rows are in the DataFrame five_bowls.merge(five_bowls, on="fruit")?

• 5

• 9

• 11

• 15

• 25

• None of these

Problem 3

Suppose there are five available fruits: strawberries (red), bananas (yellow), raspberries (red), pomegranate (red), and pineapple (yellow). If Pranav orders a bowl with one fruit and tells you that the fruit is red, what is the probability he did not get strawberries?

Problem 4

The density histogram below shows the distribution of "num_toppings" for 250 unique orders in blue_bowl.

Problem 4.1

Kate orders a bowl with exactly two toppings. Which bin is her order included in?

• A

• B

• C

• D

• E

• F

• G

Problem 4.2

How many more orders were there with one topping than orders with no toppings? Give your answer as an integer rounded to the nearest multiple of 5.

Problem 5

Fill in the body of the function prep_time such that both expressions below evaluate to the same Series.

    blue_bowl.get("num_toppings").apply(prep_time)

    1.2 + 0.2 * blue_bowl.get("num_toppings")

    def prep_time(x): 
        return 

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