Statistics II for IB (EBB682B05)

To test if the length of the right arm is on average larger than the length of the left arm in a group of basketball players, all necessary information is collected. Which of the following statements is true when deciding upon applying the appropriate testing method? A. One sample T test should be used. B. Paired-samples T test should be used. C. Independent-samples T test should be used. D. Levene’s test for equality of variances needs to be carried out.

. A researcher conducted a Linear Multivariate Regression Analysis and she got the following results: • b0 = - 0.165, for beta0: t = 13.756, p = 0.000 • b1 = - 0.385, for beta1: t = -2.633, p = 0.010 • b2 = - .0118, for beta2: t = -8.877, p = 0.000 What conclusions can be made based on these results? A. Only parameter beta1 is significant at 1% significance level. B. All population parameters are significant at 1% significance level. C. The testing for individual significance resulted into failing to reject the null hypotheses. D. There is no significant parameter based on the above results.

4. Which of the following is not a part of the formula for constructing a confidence interval for the difference between two population means? A. A point estimate of the difference between the population means B. The standard error of the sampling distribution of the sample means C. The confidence level D. The values of the population means

2. Which statement is true when the confidence interval of the mean difference between Math and Language grades of a group of students is (-3.46, -0.05)? Assume that students in the sample are randomly selected from a normal population. A. Math and Language grades are both below their population averages. B. Language grades are higher on average among students. C. Math grades are higher on average among students. D. Students have statistically equal exam grades in Math and Language.

1. A researcher is interested in stress levels of students during Statistics II’s lectures. The researcher takes a sample of 12 students and measures their levels of stress first during a lecture taking place in a classroom and then during a lecture online. The data is not normally distributed. Which test should the researcher use to compare the stress levels? A. Mann–Whitney U test B. Wilcoxon rank-sum test C. Paired samples t-test D. Wilcoxon signed-rank test

How to know when should I use t-test? What is Levene's test and how to use it?