Help me answer these questions

1. For questions that require a short answer, answer as precisely as possible.

2. For questions requiring calculations, you must include the details of your calculations.

3. To get the bonus due to using RStudio, you can submit your R file with your Word document containing your answers or add your lines of code at the end of your Word document. Your codes should include your calculations for at least two of the questions and the graph showing the correlation from question 19.

11. What is the probability of making a Type I error? (Use its symbol.)

12. Imagine an example of a research question requiring a longitudinal study. (Write your research question.)

13. A population (n = 5) consists of the following scores: 0, 7, 5, 2 and 11.

a) Calculate and for the population.

b) Find the z-score for each score in the population.

14. Explain in your own words when it is appropriate to use a one-tailed test rather than a two-tailed test.

15. A psychology professor believes that teaching students the active recall method influences students' grades at the end of the course. He takes a sample of 20 students and teaches them this method and how to apply it. The average score for this sample is M = 568. The population of students typically has a normal distribution with 400 and = 100.

a) Can the professor conclude that students who apply this method obtain significantly better results than the general population? Use a one-sided test with .01.

b) Calculate Cohen's d to estimate the effect size.

c) Write a sentence demonstrating how the results of hypothesis testing and effect size measurement would appear in a research report.

16. McAllister et al. (2012) compared college football and hockey players with college athletes playing non-contact sports to determine if exposure to head impacts over the course of a season had an effect on cognitive performance. In the study, tests of new learning performance were significantly worse for athletes playing contact sports than for those playing non-contact sports. The following table presents data similar to the results obtained in the study.

Athltes (Sport sans contact)	Athltes (Sport avec contact)
11	8
9	5
8	10
10	4
14	8
8	7
7	11
13	3

a) Choose your hypothesis test, do your calculations and answer this question: Are the results of athletes playing contact sports significantly lower than those of athletes playing non-contact sports? (Use a one-tailed test with an alpha of 0.05.)

b) Calculate the value of r2 (the percentage of variance explained by these data) and give its interpretation.

c) Suppose that your samples are not equal, and that in the list corresponding to athletes with contact, you are missing 2 values. What approach can you use to work around this problem?

17. A researcher is conducting an experiment comparing two treatment conditions, with 25 scores in each treatment condition.

a) For a t-test with independent measurements, how many subjects are needed for the experiment?

b) For a repeated measures t-test, how many subjects are needed for the experiment?

c) For a t-test with paired measures, how many subjects are needed for the experiment?

18. A researcher conducts an experiment comparing four treatment conditions with a separate sample of n=10 in each treatment. An ANOVA is used to evaluate the data and the results of the ANOVA are presented in the following table. Fill in any missing values in the table and interpret the results. (Hint: start with the values in column dl).

	SC	dl	CM	F
Traitement			10
Erreur
Total	174

19. Identifying people at high risk for Alzheimer's disease usually involves a lengthy series of cognitive tests. However, researchers have developed a 7-Minute Screen, which is a quick and easy way to achieve the same goal. The question is whether the 7-minute screening is as effective as the full series of tests. To answer this question, Ijuin et al. (2008) administered both tests to a group of patients and compared the results. The following data represent results similar to those obtained in the study.

Patient	cran 7-minute	Tests Cognitifs
1	5	13
2	10	21
3	12	24
4	10	22
5	6	16
6	9	15
7	6	11
8	7	22
9	16	27
10	6	15

a) Calculate the Pearson correlation to measure the degree of relationship between the two test results.

b) Is the correlation statistically significant? Use a two-tailed test with a .01.

c) What percentage of variance in cognitive scores is predicted from the 7-minute screen scores? (Calculate the value of r2.)

RStudio users: Don't forget to create a graph from the table provided in this question.

20. A colleague who has not yet taken the PSYC2127 course comes to see you in a panic. She works as a research assistant for a professor who studies the differences between learning methods. She has been given data to analyze but is unsure of what approach to take. For this data, they used a repeat test to compare study methods (studying by rereading only, studying by answering questions, and studying by creating questions yourself). Here are the scores obtained by 6 students:

	Traitement
tudiants	Rviser en relire seulement	Rviser avec des questions	Rviser en crant des questions
1	2	5	8
2	6	9	12
3	8	10	12
4	6	13	11
5	5	8	11
6	3	9	6

Statistiques Infrentielles
	SC	dl	CM	F
Inter-Sujets
Traitement
Erreur
Total

As you have learned to do the calculations and reassure her, and tell her that you can help her!

a) Show him how to write the null hypothesis in symbols

b) Show him how to write an alternative hypothesis in symbols

c) There is more than one possibility for the alternative hypothesis. Tell him how much and explain to him why

d) Use the appropriate steps to complete each of the boxes in the inferential statistics table e) What should she do next? In other words, now that she has her analysis of variance, are there any other steps that will need to be done and why? (Be specific and give a complete answer.)