Does going to university in a different country affect your mental health? A Japanese international university surveyed its students in 2018 and published a study the following year that was approved by several ethical and regulatory boards.
The study found that international students have a higher risk of mental health difficulties than the general population. Explore the students data using PostgreSQL to find out if this is true and see if the length of stay is a contributing factor.
Here is a data description of the fields you may find helpful. The full dataset is in one table with 50 fields and, according to the survey, 268 records. Each row is a student.
| Field Name | Description |
|---|---|
| inter_dom | Types of students |
| japanese_cate | Japanese language proficiency |
| english_cate | English language proficiency |
| academic | Current academic level |
| age | Current age of student |
| stay | Current length of stay in years |
| todep | Total score of depression (PHQ-9 test) |
| tosc | Total score of social connectedness (SCS test) |
| toas | Total score of Acculturative Stress (ASISS test) |
Your task will be to do the following exploratory analysis:
- Count the number of all records, and all records per student type
- Filter the data to see how it differs between the student types
- Find the summary statistics of the diagnostic tests for all students
- Summarize the data for international students
- See if length of stay impacts the test scores
-- Start coding here...
SELECT *
FROM students;Count the number of records in the dataset to confirm you have the expected number of records, then see how many records you have for each student type. Use the aliases total_records and count_inter_dom.
SELECT COUNT(*) AS total_records, COUNT(inter_dom) AS count_inter_dom
FROM students
GROUP BY inter_dom;Explore the data for each student type by doing three queries that filter for each of the student types represented in the table.
SELECT inter_dom, stay_cate, age
FROM students
WHERE stay_cate = 'Long' AND age BETWEEN 25 AND 30;Find the summary statistics for each diagnostic test using the aggregrate functions for minimum, maximum, and average. Round the averages to two decimal places and use aliases to keep the output clean. Your aliases should be min_phq, max_phq, and avg_phq; repeat this structure for the other two tests.
SELECT stay,
ROUND(AVG(todep), 2) AS average_phq,
ROUND(AVG(tosc), 2) AS average_scs,
ROUND(AVG(toas), 2) AS average_as
FROM students
WHERE inter_dom = 'Inter'
GROUP BY stay
ORDER BY stay DESC;