For this assignment, you will read a few example studies and try to figure out the null and alternative hypotheses, and what the type I and type II errors would be in those situations.
Here’s an Example to give you an idea about what you’ll be doing: A researcher is interested in testing whether a new therapy for adolescent depression works to reduce depression. He measures depression before and after the therapy and he expects depression levels to decrease after therapy.
Hypotheses:
Null Hypothesis: H0: depression after therapy depression before therapy (in other words, depression is the same or worse after therapy than it was before therapy);
Alternative Hypothesis: H1: depression after therapy < depression before therapy (in other words, depression is lower after therapy than it was before). This hypothesis is
directional
· Type I error: The researcher concludes that depression decreases after therapy, when in reality depression is the same or worse after therapy (in other words, the researcher concludes that the therapy works to reduce depression, when in reality it did not!).
· Type II error: The concludes that depression levels are the same after therapy, when in reality they get better (in other words, the researcher concludes that the therapy did not work to reduce depression, when in reality it did!)
For some questions, you’ll get to choose from multiple choice options. For others, you’ll have to write out our own response.
1- Multiple choice
Scenario A. A researcher wants to test whether watching virtual reality (VR) nature experiences results in lower stress levels than watching standard nature videos. Participants are randomly assigned to either experience a 10-minute VR forest simulation or watch a 10-minute nature video on a regular screen. Stress is measured afterward using heart rate and self-report.
What is the null hypothesis for this scenario?
Stress after VR nature < stress after standard video
Stress after VR nature ≥ stress after standard video
Stress after VR nature ≤ stress after standard video
Stress after VR nature > stress after standard video
Stress after VR nature = stress after standard video
2-Multiple choice
What is the alternative hypothesis for scenario A?
Stress after VR nature ≤ stress after standard video
Stress after VR nature ≥ stress after standard video
Stress after VR nature = stress after standard video
Stress after VR nature > stress after standard video
Stress after VR nature < stress after standard video
3-
What would be a type I error for scenario A?
See the example question for guidance!
4- What would be a type II error for scenario A?
5-Multile choice
Scenario B. A researcher investigates whether improving students’ sleep hygiene (e.g., consistent bedtime, no screens before bed, relaxation routine) increases cognitive performance in college students. Students are randomly assigned to follow a two-week sleep hygiene plan or maintain their normal sleep routine. After two weeks, all students complete a problem-solving test.
Is this a directional or non-directional hypothesis?
Non-Directional
Directional
6- What is the null hypothesis for scenario B?
7- What is the alternative hypothesis for scenario B?
8-Multiple Choice
What would be a type I error for scenario B?
The researcher concludes that the sleep hygiene plan improves cognitive performance when, in reality, it makes cognitive performance better.
The researcher concludes that the sleep hygiene plan improves cognitive performance when, in reality, it does not.
The researcher concludes that the sleep hygiene plan does not improve cognitive performance when, in reality, it does improve performance.
The researcher concludes that the sleep hygiene plan does not improve cognitive performance when, in reality, it does not improve performance.
9-Multiple Choice
What would be a type II error for scenario B?
The researcher concludes that the sleep hygiene plan improves cognitive performance when, in reality, it makes cognitive performance better.
The researcher concludes that the sleep hygiene plan improves cognitive performance when, in reality, it does not.
The researcher concludes that the sleep hygiene plan does not improve cognitive performance when, in reality, it does improve performance.
The researcher concludes that the sleep hygiene plan does not improve cognitive performance when, in reality, it does not improve performance.
10-Multiple Choice
Scenario C. David sees an ad for a running app, called FunRun, that claims to provide personalized training plans that significantly reduce your 5k race time time (in other words, it claims to make you run a 5k in LESS time), as compared to your regular training regimen.
Is this a directional or non-directional hypothesis?
Non-Directional
Directional
11-Multiple choice
What is the null hypothesis for scenario C?
5K time with app = 5k time without the app
5K time with app ≠ 5k time without the app
5K time with app ≤ 5k time without the app
5K time with app < 5k time without the app
5K time with app > 5k time without the app
5K time with app ≥ 5k time without the app
12-multiple choice
What is the alternative hypothesis for scenario C?
5K time with app ≤ 5k time without the app
5K time with app > 5k time without the app
5K time with app < 5k time without the app
5K time with app ≠ 5k time without the app
5K time with app = 5k time without the app
5K time with app ≥ 5k time without the app
13- What would be a Type I error for scenario C?
14- What would be a type II error for scenario C?
15-Multiple Choice
Scenario D. A researcher examines whether listening to AI-composed music produces different emotional responses than human-composed music. Participants listen to either human or AI composed music and rate how emotionally moved they feel afterward on a standardized scale.
Should we test this using a directional or non-directional hypothesis?
Non-Directional
Directional
16-Multiple Choice
What is the null hypothesis for scenario D?
Emotional response to AI music = emotional response to human music
Emotional response to AI music > emotional response to human music
Emotional response to AI music ≠ emotional response to human music
Emotional response to AI music < emotional response to human music
17-Multiple Choice
What is the alternative hypothesis for scenario D?
Emotional response to AI music < emotional response to human music
Emotional response to AI music > emotional response to human music
Emotional response to AI music ≠ emotional response to human music
Emotional response to AI music = emotional response to human music
18-Multiple Choice
What is a type I error for Scenario D?
The researcher concludes that AI and human music evoke similar emotions when, in fact, there is no difference in the emotional response they evoke.
The researcher concludes that AI and human music evoke different emotions when, in fact, they evoke similar responses.
The researcher concludes that AI and human music evoke different emotions when, in fact, human generated music evokes a greater emotional response.
The researcher concludes that AI and human music evoke similar emotions when, in fact, they evoke different emotional responses.
19-Multiple Choice
What is a type II error for Scenario D?
The researcher concludes that AI and human music evoke different emotions when, in fact, human generated music evokes a greater emotional response.
The researcher concludes that AI and human music evoke similar emotions when, in fact, they evoke different emotional responses.
The researcher concludes that AI and human music evoke similar emotions when, in fact, there is no difference in the emotional response they evoke.
The researcher concludes that AI and human music evoke different emotions when, in fact, they evoke similar responses.
