The request

From Megan Collins, Head of Sales
Your goal
Using order lines with quantity > 0 from orders with status 'completed' placed in 2025, compute each order's value (sum of quantity * unit_price * (1 - discount_pct / 100)) and attach the customer's segment. Set result to a DataFrame with columns segment, n_orders, median_value and mean_value (both rounded to 2), one row per segment, sorted by segment A to Z, index reset. Draw both distributions with sns.histplot and hue.
- Use the
customersDataFramenot done yet - Use the
ordersDataFramenot done yet - Show exactly
segmentn_ordersmedian_valuemean_valuenot done yet
Your code
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Reference solution
| customer_id | first_name | last_name | city | |
|---|---|---|---|---|
| 1 | Owen | Hudson | owen.hudson@icloud.com | San Francisco |
| 2 | Douglas | Mendoza | dmendoza69@gmail.com | Atlanta |
| 3 | Henry | Brooks | hbrooks@lakesidecafe.com | Los Angeles |
| 4 | Brian | Graham | bgraham@bluecedarhomes.com | Seattle |
Mote checks your result
Press Run. Each row that matches the goal becomes a firefly in your lantern.
What Megan gets, and why
DataFrames
Loaded for you as pandas DataFrames, plus pd and np.
customers2,018 rows · 9 columns
customer_idintegerfirst_namevarcharlast_namevarcharemailvarcharcityvarcharstatevarcharsignup_datedatesegmentvarcharreferral_sourcevarchar
| customer_id | first_name | last_name | city | state | signup_date | segment | referral_source | |
|---|---|---|---|---|---|---|---|---|
| 1 | Owen | Hudson | owen.hudson@icloud.com | San Francisco | CA | 2022-06-02 | consumer | search |
| 2 | Douglas | Mendoza | dmendoza69@gmail.com | Atlanta | GA | 2022-06-02 | consumer | NaN |
| 3 | Henry | Brooks | hbrooks@lakesidecafe.com | Los Angeles | CA | 2022-06-04 | business | NaN |
| 4 | Brian | Graham | bgraham@bluecedarhomes.com | Seattle | WA | 2022-06-06 | business | |
| 5 | Kyle | Jimenez | kjimenez27@yahoo.com | Indianapolis | IN | 2022-06-07 | consumer | NaN |
orders12,000 rows · 7 columns
order_idintegercustomer_idintegerorder_datetimestampstatusvarcharchannelvarcharshipping_feedecimalcoupon_codevarchar
| order_id | customer_id | order_date | status | channel | shipping_fee | coupon_code |
|---|---|---|---|---|---|---|
| 1001 | 125 | 2023-01-01 20:51:19 | completed | web | 0.00 | NaN |
| 1002 | 156 | 2023-01-02 07:58:46 | completed | web | 0.00 | NaN |
| 1003 | 22 | 2023-01-02 10:25:27 | completed | marketplace | 4.99 | WELCOME10 |
| 1004 | 48 | 2023-01-02 11:21:51 | completed | marketplace | 4.99 | WELCOME10 |
| 1005 | 82 | 2023-01-02 11:43:36 | completed | web | 0.00 | WELCOME10 |
order_items30,338 rows · 6 columns
order_item_idintegerorder_idintegerproduct_idintegerquantityintegerunit_pricedecimaldiscount_pctdecimal
| order_item_id | order_id | product_id | quantity | unit_price | discount_pct |
|---|---|---|---|---|---|
| 1 | 1001 | 121 | 9 | 31.99 | 0.00 |
| 2 | 1001 | 154 | 3 | 11.99 | 0.00 |
| 3 | 1002 | 154 | 4 | 11.99 | 0.00 |
| 4 | 1002 | 194 | 1 | 149.00 | 0.00 |
| 5 | 1002 | 193 | 2 | 19.99 | 0.00 |
products120 rows · 8 columns
product_idintegernamevarcharcategoryvarcharsubcategoryvarcharunit_pricedecimalunit_costdecimallaunched_ondateis_activeboolean
| product_id | name | category | subcategory | unit_price | unit_cost | launched_on | is_active |
|---|---|---|---|---|---|---|---|
| 101 | Vale Velvet Loveseat | Furniture | Sofas | 1659.00 | NaN | 2023-09-11 | true |
| 102 | Alder Oak Coffee Table | Furniture | Tables | 919.00 | 503.50 | 2024-05-16 | true |
| 103 | Orchard Rattan Dining Chair | Furniture | Chairs | 789.00 | 429.87 | 2023-05-27 | true |
| 104 | Upland Oak Bookcase | Furniture | Storage | 429.00 | 214.70 | 2022-12-20 | true |
| 105 | Avery Leather Bed Frame | Furniture | Beds | 449.00 | 232.70 | 2021-08-31 | true |
returns1,673 rows · 5 columns
return_idintegerorder_item_idintegerreturned_ondatereasonvarcharrefund_amountdecimal
| return_id | order_item_id | returned_on | reason | refund_amount |
|---|---|---|---|---|
| 1 | 14 | 2023-01-10 | damaged | 83.69 |
| 2 | 42 | 2023-01-10 | wrong_item | 19.99 |
| 3 | 105 | 2023-01-14 | wrong_item | 10.99 |
| 4 | 24 | 2023-01-16 | changed_mind | 26.99 |
| 5 | 126 | 2023-01-16 | late | 20.99 |
employees60 rows · 8 columns
employee_idintegerfirst_namevarcharlast_namevarchardepartmentvarchartitlevarcharmanager_idintegerhire_datedatesalaryinteger
| employee_id | first_name | last_name | department | title | manager_id | hire_date | salary |
|---|---|---|---|---|---|---|---|
| 1 | Catherine | Hale | Executive | Chief Executive Officer | NaN | 2016-03-01 | 285000 |
| 2 | Robert | Kim | Executive | Chief Operating Officer | 1 | 2017-01-09 | 235000 |
| 3 | Megan | Collins | Sales | Head of Sales | 1 | 2018-04-16 | 172000 |
| 4 | Chloe | Gutierrez | Sales | Account Executive | 3 | 2020-01-21 | 72000 |
| 5 | Frank | Bell | Sales | Account Executive | 3 | 2023-05-21 | 73000 |
web_sessions40,000 rows · 7 columns
session_idintegercustomer_idintegerstarted_attimestampdevicevarcharsourcevarcharpages_viewedintegerconvertedboolean
| session_id | customer_id | started_at | device | source | pages_viewed | converted |
|---|---|---|---|---|---|---|
| 1 | NaN | 2023-01-01 23:02:24 | mobile | paid | 1 | false |
| 2 | 18 | 2023-01-01 15:07:49 | desktop | paid | 1 | false |
| 3 | NaN | 2023-01-01 16:55:46 | desktop | direct | 7 | false |
| 4 | NaN | 2023-01-01 12:43:28 | mobile | organic | 3 | false |
| 5 | NaN | 2023-01-01 13:06:21 | mobile | social | 2 | false |
marketing_spend3,276 rows · 3 columns
spend_datedatechannelvarcharamountdecimal
| spend_date | channel | amount |
|---|---|---|
| 2023-01-01 | paid | 492.99 |
| 2023-01-01 | 37.38 | |
| 2023-01-01 | social | 200.53 |
| 2023-01-02 | paid | 709.13 |
| 2023-01-02 | 64.13 |
The lesson
histplot draws a distribution
sns.histplot is seaborn’s histogram. Same pattern as every seaborn function: the table, then
column names.
ax = sns.histplot(data=per_order, x="value", bins=30)
Compared with ax.hist, the gain is hue=: one call draws a histogram per group, in different
colors, with a legend.
ax = sns.histplot(data=per_order, x="value", hue="segment", bins=30,
element="step", stat="density", common_norm=False, kde=True)
element="step"draws outlines instead of filled bars, so overlapping groups stay readable.stat="density"withcommon_norm=Falsescales each group to its own size. Without it, the 3,162 consumer orders would dwarf the 1,133 business ones and you’d compare group sizes instead of shapes.kde=Trueadds a smooth curve over each histogram, an estimate of the distribution’s shape.
The numbers behind the shapes
A chart shows the difference; numbers measure it. Named aggregation gives one row per segment:
per_order.groupby("segment", as_index=False).agg(
n_orders=("order_id", "size"),
median_value=("value", "median"),
mean_value=("value", "mean"),
)
# segment n_orders median_value mean_value
# business 1133 706.90 1059.42
# consumer 3162 183.77 348.31
A business order is typically about four times a consumer order. Business accounts placed 26% of 2025’s completed orders but brought 52% of the revenue. In both groups the mean is far above the median, because a few very large baskets pull it up: the medians are the fairer “typical order”.
Trimming the view, not the data
A handful of orders above $3,000 stretch the x-axis so far that the bulk of the chart is squeezed
into the left edge. It’s fine to draw only orders up to $3,000 and say so in the axis label. The
numbers in result still use every order. Trim what you show, never what you compute, and tell the
reader where you cut.
Common mistakes
- Plotting order lines instead of orders: a basket of five lines would count five times.
- Merging the segment with a key that isn’t unique on the
customersside.validate="many_to_one"stops that early. - Comparing two groups of very different sizes with raw counts instead of densities.
- Quoting only the means of skewed groups.
- Leaving
kde=Trueon a small group. With a few dozen values the smooth curve invents bumps that aren’t there; trust the bars and the medians.
Lantern lit!
Practised: seabornhistplothuekdedistributionmedian
- Solved
- No hints
- First run
