### Table of Contents

The outline of your notebook will show up here. You can include headings in any text cell by starting a line with `# `

, `## `

, `### `

, etc., depending on the desired title hierarchy.

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, and that social connectedness (belonging to a social group) and acculturative stress (stress associated with joining a new culture) are predictive of depression.

Explore the `students`

data using PostgreSQL to find out if you would come to a similar conclusion for international students and see if the length of stay is a contributing factor.

Here is a data description of the columns you may find helpful.

Field Name | Description |
---|---|

`inter_dom` | Types of students (international or domestic) |

`japanese_cate` | Japanese language proficiency |

`english_cate` | English language proficiency |

`academic` | Current academic level (undergraduate or graduate) |

`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) |

```
-- Run this code to save the CSV file as students
SELECT *
FROM 'students.csv';
```

```
-- Start by counting all of the records in the data,
SELECT COUNT(*) AS number_of_students
FROM students;
```

```
-- then all records per student type to see how the records are categorized
-- and scored.
SELECT *
FROM students
WHERE inter_dom = 'Inter';
```

```
-- then all records per student type to see how the records are categorized
-- and scored.
SELECT *
FROM students
WHERE inter_dom = 'Dom';
```

```
-- Find the summary statistics of the diagnostic tests for all students using -- aggregate functions, rounding the test scores to two decimal places,
-- remembering to use aliases.
SELECT ROUND(SUM(todep), 2) AS sum_todep, ROUND(AVG(todep), 2) AS avg_todep, ROUND(MIN(todep), 2) AS min_todep, ROUND(MAX(todep), 2) AS max_todep, ROUND(SUM(tosc), 2) AS sum_tosc, ROUND(AVG(tosc), 2) AS avg_tosc, ROUND(MIN(tosc), 2) AS min_tosc, ROUND(MAX(tosc), 2) AS max_tosc, ROUND(SUM(toas), 2) AS sum_toas, ROUND(AVG(toas), 2) AS avg_toas, ROUND(MIN(toas), 2) AS min_toas, ROUND(MAX(toas), 2) AS max_toas
FROM students;
```

```
-- Repeat this to summarize the data for international students only.
SELECT ROUND(SUM(todep), 2) AS sum_todep, ROUND(AVG(todep), 2) AS avg_todep, ROUND(MIN(todep), 2) AS min_todep, ROUND(MAX(todep), 2) AS max_todep, ROUND(SUM(tosc), 2) AS sum_tosc, ROUND(AVG(tosc), 2) AS avg_tosc, ROUND(MIN(tosc), 2) AS min_tosc, ROUND(MAX(tosc), 2) AS max_tosc, ROUND(SUM(toas), 2) AS sum_toas, ROUND(AVG(toas), 2) AS avg_toas, ROUND(MIN(toas), 2) AS min_toas, ROUND(MAX(toas), 2) AS max_toas
FROM students
WHERE inter_dom = 'Inter';
```

```
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;
```