You do not need to define or take care of missing values. Stata will recognise these automatically after importing the dataset. Do not delete any da

Assessment 3 Codebook

You do not need to define or take care of missing values. Stata will recognise these automatically after importing the dataset. Do not delete any data or participant from the dataset unless the codebook specifically instructs you to do so.

If there are no specific instructions in regards to values that are not valid, delete the value itself but not the participant. In all other cases, follow the specific instructions below.

No Name Label Values Other information

1 ID Participant ID -- 2 Age Age Age in years

Valid Range: 18-30 Participants with values above or below the valid range need to be deleted from the dataset completely (not just the age value)

3 Ethnicity_SimpEthnicity Simplified 1 Caucasian or White

2 All Other 4 GenderSimpGender Simplified 1 Woman

2 Man

3 Other 5 SexOrSimpSexual Orientation Simplified 1 Straight/Heterosexual

2 Gay/Lesbian/Bisexual

3 Unsure/Refused to answer 6 Relationship Relationship status 1 In a relationship

2 Not in a relationship

3 Unsure 7 Country_bornCountry of birth 1 Australia

2 New Zealand

3 United Kingdom

4 European Union

5 Europe (excluding EU)

7 North America

8 South America

9 Africa

10 China

11 Asia (excluding China and Oceania)

14 Oceania (excluding Australia and New Zealand) Number are correct although there are some missing such as 6

8 Area_liveLiving area 1 Major City

2 Inner Regional

3 Outer Regional

4 Remote

5 Very Remote 9 Life_RoshnaEver used: Roshna0 No

1 Yes Roshna is a fake drug (substance). It is part of the questionnaire to identify people who want to make themselves look like they are using more drugs than they truly are. This is a common problem in substance use research. Any individual that said yes to using this drug needs to be completely removed from the dataset.

10 Life_MethEver used: Methamphetamine ('ICE', 'Crystal') 0 No

1 Yes This substance is defined as illicit (illegal).

11 Life_SteroidsEver used: Steroids 0 No

1 Yes This substance is defined as illicit.

12 Life_OpiodsEver used: Opioids (heroin, morphine, methadone) 0 No

1 Yes This substance is defined as illicit.

13 Life_AlcoholEver used: Alcohol (beer, wine, spirits) 0 No

1 Yes 14 Life_TobaccoEver used: Tobacco products (cigarettes, cigars) 0 No

1 Yes 15 Life_THCEver used: Cannabis (marijuana, pot, grass, hash) 0 No

1 Yes This substance is defined as illicit.

16 Life_MDMAEver used: MDMA ('Ecstasy') 0 No

1 Yes This substance is defined as illicit.

17 Life_GHB_GBLEver used: GHB/GBL ('G', 'Liquid E', 'Liquid X') 0 No

1 Yes This substance is defined as illicit.

18 Life_HallucinogensEver used: Hallucinogens (LSD, acid, magic mushrooms, ketamine) 0 No

1 Yes This substance is defined as illicit.

19 Life_CocaineEver used: Cocaine ('Coke, 'Crack') 0 No

1 Yes This substance is defined as illicit.

20 Life_AmphetaminesEver used: Amphetamines (speed, mephedrone) 0 No

1 Yes This substance is defined as illicit.

21 Year_MethUsed past 12months: Methamphetamine ('ICE', 'Crystal') 0 No

1 Yes This substance is defined as illicit.

22 Year_SteroidsUsed past 12months: Steroids 0 No

1 Yes This substance is defined as illicit.

23 Year_OpiodsUsed past 12months: Opioids (heroin, morphine, methadone) 0 No

1 Yes This substance is defined as illicit.

24 Year_AlcoholUsed past 12months: Alcohol (beer, wine, spirits) 0 No

1 Yes 25 Year_TobaccoUsed past 12months: Tobacco products (cigarettes, cigars) 0 No

1 Yes 26 Year_THCUsed past 12months: Cannabis (marijuana, pot, grass, hash) 0 No

1 Yes This substance is defined as illicit.

27 Year_MDMLUsed past 12months: MDMA ('Ecstasy') 0 No

1 Yes This substance is defined as illicit.

28 Year_GHB_GBLUsed past 12months: GHB/GBL ('G', 'Liquid E', 'Liquid X') 0 No

1 Yes This substance is defined as illicit.

29 Year_HallucinogensUsed past 12months: Hallucinogens (LSD, acid, magic mushrooms, ketamine) 0 No

1 Yes This substance is defined as illicit.

30 Year_CocaineUsed past 12months: Cocaine ('Coke, 'Crack') 0 No

1 Yes This substance is defined as illicit.

31 Year_AmphetaminesUsed past 12months: Amphetamines (speed, mephedrone) 0 No

1 Yes This substance is defined as illicit.

32 Alcohol_howoftenAudit C: Past 3 months, how often did you have a drink containing alcohol? 1 Monthly or less

2 Two to four times a month

3 Two to three times a week

4 Four times or more per week These three questions are part of the Alcohol Use Disorder Identification Test (short: AUDIT-C). This score can be complicated to calculate. You can copy this into the Numeric Expression field to calculate the variable:

Alcohol_howoften + (Alcohol_StandardDrinks - 1) + (Alcohol_Binge - 1)

The AUDIT-C Score can be divided into four categories:

0 3: Low Risk

4 6: Increasing Risk

7 9: High Risk

10+ : Potentially dependent

33 Alcohol_StandardDrinksAudit C: standard drinks containing alcohol on a typical day/night drinking 1 1-2

2 3-4

3 5-6

4 7-9

5 10 or more 34 Alcohol_BingeAudit C: Binge Drinking (consuming 6 standard drinks or more in one sitting) 1 Never

2 Less than monthly

3 Monthly

4 Weekly

5 More than once a week 35 Self_efficacy1 TO Self_efficacy8 This is a scale measurement consisting of 8 items asking participants about their confidence to be able to resist the urge to use drugs in specific situations. Each item is ranked on a Likert-scale from 0 (not at all confident) to 100 (very confident).

Individual items can be transformed into a summary score in two steps:

adding individual answers up

calculating an average score by dividing it by the number of items in the final scale

The final scale has a range from 0 to 100.

36 Coping_1 TO Coping_18 This is a scale measurement originally consisting of 48 items of which 18 were selected to be included in this study. Each item describes a specific coping mechanism for stressful situations and is ranked on a Likert-Scale from 1 (not all all) to 5 (very much)

Since only a part of the questions made it into the survey, the quality of this scale is unclear. It is assumed that just adding the individual values up will lead to a true scale. The scale has a range of 18 to 90.

37 MentalHealthCont_1 TO MentalHealthCont_14 The Health Continuum Short Form consists of 14 items measuring the emotional and psychological wellbeing of participants. Each item is measured on an individually-defined six-point Likert-Scale:

0 Never

1 Once or twice

2 About once a week

3 About 2 or 3 times a week

4 Almost every day

5 Every day

It can be turned into an overall mental health continuum summary score between 0 and 70.

Assessment 2 Marking Criteria

Task 1

Domain Points possible

Identifies all non-valid variables and handles them according to the instructions provided 6

Correctly creates summary scores, analysis internal consistency correctly. 7

Correctly creates categorical variables. 3

Correctly recodes variable 1

Total Task 1 17

Task 2

Domain Points possible

Appropriate describes data using correct measurement of location and dispersion 8

Uses appropriate graphical presentation of data 2

Total Task 2 10

Task 3 Question 1

Domain Points possible

Hypotheses appropriate 2

Assumptions checked and reported correctly 5

Test statistic reported and interpreted correctly, other relevant data reported 8

Appropriate discussion of clinical relevance 2

Total Task 3 Question 1 17

Task 3 Question 2

Domain Points possible

Hypotheses appropriate 2

Assumptions checked and reported correctly 5

Test statistic reported and interpreted correctly, other relevant data reported 6

Appropriate discussion of clinical relevance 2

Total Task 3 Question 2 15

Task 3 Question 3

Domain Points possible

Hypotheses appropriate 2

Assumptions checked and reported correctly 5

Test statistic reported and interpreted correctly, other relevant data reported 7

Appropriate discussion of clinical relevance 3

Total Task 3 Question 3 17

Task 4 Question 4

Domain Points possible

Hypotheses appropriate 2

Assumptions checked and reported correctly 10

Test statistic reported and interpreted correctly, other relevant data reported 10

Appropriate discussion of clinical relevance 2

Total Task 3 Question 4 24

You must attach the Stata output (at the end of your assessment). If you do not provide the relevant outputs for an activity (or part thereof), a penalty of 50% for the respective task will be applied. You can attached a screenshot of Stata output (the snipping tool for Windows and Mac is helpful), or copy and paste the output and syntax into a text box. If you select a monospaced font (e.g. Consolas, Courier New) then the formatting of the tables will line up and match how it looks in Stata.

Assessment 2 Instructions and Task

The dataset you will analyse for this assessment comes from a cross-sectional survey on substance use and mental health in Sydney University students and was conducted in November 2019. The dataset comes with 74 variables and 1433 participants you can find the codebook for the dataset on Canvas. Please read all instructions and have a look at the codebook before you start! If you have any questions, have a look at the FAQ provided on Canvas. If you have any further questions please ask them during the Zoom Meetings or use the discussion board on Canvas.

Structure: There is no specific structure for this assessment, please just use the Tasks as headings. There is no need for an introduction or a summary, ensure to state all information that is needed for each of the tasks. Ensure to copy and paste the full Stata Output at the end of the assessment.

Use snipping tool (on Windows or Mac) to create screenshots, or copy/paste the output (including the command) into a text box with a monotype font (e.g. Consolas or Courier New) to make the formatting correct.

Note: The assessment is divided into three separate tasks. Task 1 and 2 will assist and guide you to ensure the dataset is ready and you have provided sufficient information on the assessment itself this is needed to be able to answer the questions in Task 3.

Task 1: Data cleaning and Preparation

Import the data into Stata and code the data as per codebook provided on Canvas.

Check the data and clean according to the specific instructions provided in the codebook depending on the variable. Make sure to provide us with information on the cleaning process stating the participant ID.

New variables are needed for upcoming tasks. Create the following variables:

Two new binary variables showing the use of any illicit substance in a participants life and in the last year (Yes/No). Note: You may need two steps to create these variables.

Create a summary score variable for: (I) Self Efficacy, (II) Coping, and (III) Mental Health. Analyse and comment on the internal consistency of the variable. Adjust the summary as necessary based on your analysis. If you undertake adjustments, describe the steps you have undertaken and comment on the internal consistency of the final summary score variable.

Create a summary score and a categorical variable for the AUDIT Scores. You do not need to analyse the internal consistency of this scale.

In the variable Area_live combine Inner Regional and Outer Regional into one value titled Regional; combine Remote and Very Remote into one value titled Remote.

Task 2: Describing the sample

Describe the sample in the dataset. You need to report on the following variables: Age, Ethnicity, Living Area, Gender, Sexual Orientation, Relationship Status, Lifetime and Past Year Use of Illicit Substances, the summary scores for Self-Efficacy, Coping, and Mental Health as well as the summary scores and categories for the AUDIT C. Assess the normality of all continuous variables using Option 1 discussed Module 3 (3.5.1 Normality Test). Visualise the data for two categorical variables using appropriate graphs.

Note: Since you analysed the normality here, you can just briefly comment under upcoming analysis and refer back to this point. You do not need to analyse the normality of a variable more than once as the data stays the same.

Task 3: Analysis

Analyse the data using the most appropriate statistical methods to answer the following questions:

Is there a difference in

coping scores between living areas?

mental health scores between living areas?

Is there a difference in AUDIT-C scores between participants who used illicit substances in the past year and those who did not?

Is there a difference in lifetime illicit substance use by

Gender?

Living Area?

Sexual Orientation?

Relationship Status?

What is the predicted mental health continuum score for a hypothetical person with a coping score of 70?

For all questions in Task 3, you must report the following:

hypotheses,

checking assumptions,

report test statistic and other relevant results,

comment on clinical significance of the findings.

Use this as the structure for this part of the assessment. You do not need to state a research question.