Module 4 - Capstone - Exercice 8 - Grader Error : The number of rows in success_rate_df is less than expected

[Christophe_Lancien]

Bug in Capstone Exercise 8 – Grader wrongly flags correct solution

Hi everyone,

I’m reporting what appears to be a bug in the grader for Capstone – Exercise 8: Success Rates by Inspection Type.

Context

The instructions ask us to:

• Select INSPECTION_TYPE
• Count total inspections per type (alias: total_inspections)
• Compute pass_rate as % of inspections with SCORE ≤ 13
• Compute avg_score using AVG(SCORE)
• Filter out NULL scores
• Only include rows with at least 5 inspections
• Group by INSPECTION_TYPE
• Order by pass_rate DESC

I implemented all of this strictly as instructed, and the resulting DataFrame matches the expected output exactly, including all column values, aliases, and sorting.

My Output

INSPECTION_TYPE	total_inspections	pass_rate	avg_score
Reopening Inspection	736	58.152174	16.722826
Re-inspection	13456	37.225030	27.152125
Initial Inspection	33171	34.237738	27.753037
Second Compliance Inspection	54	29.629630	30.648148
Compliance Inspection	643	17.729393	35.023328

This is a perfect match with the “Expected Output” shown by the graded lab.

Grader Feedback (Incorrect)

“Failed test case: The number of rows in success_rate_df is less than expected. Make sure you did not filter out any additional rows, and that you are grouping by the correct column.”

This is clearly a false negative.

All other tests passed

• I’ve completed all other exercises in this Capstone with 10/10.
• I have a 100% score in this entire specialization.
• This is the only failing case, and I’ve debugged it fully.

Request

Please investigate this grader issue. The output is correct and the error seems to stem from:

• A hardcoded row count expectation
• Or a bug in filtering logic inside the grader

Happy to provide SQL code or notebook upon request.

Thanks!

[Christophe_Lancien]

This API key problem is not related…
@MiloAndelic could you please remove your posts from this thread, since you did the right thing by creating a proper thread on this matter ? Thank you

The main problem with exercice 8 is still unresolved.
Anyone is facing the same grading issue or managed to get through it ?

[chris.favila]

Hi Christophe, and thank you for reporting! We’ll look into this today.

[chris.favila]

And yes please send me your notebook via direct message so we can replicate the issue. Thanks!

[Christophe_Lancien]

Hi @chris.favila, I just DM you with my notebook so you can replicate the issue

Thank you !

[Christophe_Lancien]

The issue was caused by the instruction:
“Only shows inspection types that have at least 5 inspections.”

As @chris.favila pointed out, this condition was triggering the grader error. Removing that part resolved the issue, and the notebook now scores 100%.

The exercise has been updated to remove this instruction while the team investigates the grader.

Thanks again!