Table of contents
- 1. Intro to Stats and Collecting Data55m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically1h 45m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables2h 33m
- 6. Normal Distribution and Continuous Random Variables1h 38m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 12m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 20m
- 14. ANOVA1h 0m
1. Intro to Stats and Collecting Data
Intro to Stats
Problem 1.3.20a
Textbook Question
Researchers in Japan tested the effect of cannabidiol (CBD) in treating late teenagers with social anxiety disorder (SAD). Thirty-seven 18- to 19-year-old teenagers with SAD took part in the study. The patients were assigned at random to receive a daily dose of either CBD or a placebo for 4 weeks. Symptoms were measured using The Fear of Negative Evaluation Questionnaire and the Liebowitz Social Anxiety Scale at the beginning and end of the treatment. (Source: Frontiers in Psychology)
a. Identify the experimental units and treatments used in this experiment.

1
Step 1: Define the experimental units. Experimental units are the individuals or objects on which the experiment is conducted. In this case, the experimental units are the 37 teenagers aged 18-19 who have social anxiety disorder (SAD).
Step 2: Identify the treatments. Treatments refer to the conditions or interventions applied to the experimental units. Here, the treatments are the daily doses of cannabidiol (CBD) and the placebo administered to the teenagers over a 4-week period.
Step 3: Explain the random assignment. Random assignment ensures that each experimental unit has an equal chance of receiving either treatment, reducing bias and confounding variables. In this study, the teenagers were randomly assigned to receive either CBD or the placebo.
Step 4: Describe the measurement tools. The researchers used The Fear of Negative Evaluation Questionnaire and the Liebowitz Social Anxiety Scale to measure symptoms of social anxiety disorder at the beginning and end of the treatment period.
Step 5: Highlight the purpose of the experiment. The goal of the study was to test the effect of CBD in treating social anxiety disorder in late teenagers by comparing symptom changes between the CBD and placebo groups.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Experimental Units
Experimental units are the smallest division of experimental material to which a treatment is applied. In this study, the experimental units are the 37 teenagers aged 18 to 19 with social anxiety disorder. Each teenager represents an individual unit that receives either the treatment (CBD) or the control (placebo) to assess the effects of the intervention.
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Random Assignment
Random assignment is a technique used to ensure that each participant has an equal chance of being assigned to any treatment group. This process helps eliminate bias and confounding variables, allowing for a more accurate assessment of the treatment's effect. In this study, the teenagers were randomly assigned to either the CBD group or the placebo group, which strengthens the validity of the results.
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Measurement Scales
Measurement scales are tools used to quantify variables in research. In this experiment, two specific scales were used: The Fear of Negative Evaluation Questionnaire and the Liebowitz Social Anxiety Scale. These scales provide a structured way to measure the severity of social anxiety symptoms before and after the treatment, allowing researchers to evaluate the effectiveness of CBD compared to the placebo.
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