6. Gravetter/Wallnau/Forzano, Essentials - Chapter 8 - End-of-chapter question 9 The psychology department is gradually changing its curriculum by increasing the number of online course offerings. To evaluate the effectiveness of this change, a random sample of n = 36 students who registered for Introductory Psychology is placed in the online version of the course. At the end of the semester, all students take the same final exam. The average score for the sample is M = 76. For the general population of students taking the traditional lecture class, the final exam scores form a normal distribution with a mean of μ = 71. If the final exam scores for the population have a standard deviation of σ = 12, does the sample provide enough evidence to conclude that the new online course is significantly different from the traditional class? Use a two-tailed test with α = .05. z-critical = ±    z =     These results indicate: Failure to reject the null hypothesis; the course has a significant effect   Rejection of the null hypothesis; the course does not have a significant effect   Failure to reject the null hypothesis; the course does not have a significant effect   Rejection of the null hypothesis; the course has a significant effect

Give me an example of a research scenario where you would use an independent samples t-test. You can set up a situation where there is an experimental group and a control group, or maybe you want to compare two other groups of people (parents and non-parents, gender, partnered and single, etc). Give us a summary of what you would want to study, who your sample participants would be, why an independent samples t-test would be the best fit, and what statistically significant results would mean. Don't forget to include your research and null hypotheses!

How do the average weekly incomes of electricians and carpenters compare? A random sample of 17 regions in the United States gave the following information about average weekly income (in dollars). (Reference: U.S. Department of Labor, Bureau of Labor Statistics.) Region 1 2 3 4 5 6 7 8 9 Electricians 464 715 597 464 736 694 744 571 806 Carpenters 542 813 513 476 688 503 789 653 474 Region 10 11 12 13 14 15 16 17 Electricians 592 594 702 579 868 598 597 654 Carpenters 489 647 676 384 817 605 556 505 Does this information indicate a difference (either way) in the average weekly incomes of electricians compared to those of carpenters? Use a 5% level of significance. (a) What is the level of significance? (b) Compute the sample test statistic.  (c) Find the P-value of the sample test statistic.

Textbook question for practise - A behavioural psychologist has developed a cognitive-behavioural therapy (CBT) technique modified from classic systematic desensitization to reduce her patients’ phobia of spiders. She decides to test the effectiveness of her new therapy approach by selecting ten patients at random to undergo the treatment for 3 months. The patients were asked to rate how much fear they feel/experience when in the presence of a spider/spiders using a scale from 0 (no fear at all) to 100 (extreme panic and fear). They were tested before and after the therapy. The ratings for each patient are as follows:   For this question, be sure to do the following: ▪ State the statistical hypotheses (using the appropriate notation). ▪ Indicate whether the research hypothesis is non-directional or directional (and how you know). ▪ Set the decision rules, which will include: o State alpha - 0.05% o Compute the degrees of freedom o Providing the critical value for the test statistic…

What type of study is this? A first-year university unit wanted to give option of online teaching to determine whether online teaching improved learning outcomes. Students were allowed to enrol into online or on-campus classes. Grades at the end of semester were compared. Select one: O Experimental O Something else O Observational

Up-County Associates is hired to estimate the proportion of county households that own three or more automobiles. They conducted their survey using a simple random sample of 250 randomly selected households and found that 23% of those households owned three or more automobiles.    (a)    Is the proportion, 23%, a parameter or a statistic? Explain.       (b)    If Up-County Associates were to continually choose simple random samples of 250 randomly selected households, each time recording the proportion of households in the sample owning three or more automobiles, what would be the “shape” of the resulting distribution of all these sample proportions?  Explain.             (c)    Suppose now that survey company Lower-County Polling also conducted a survey to determine the proportion of county households that own three or more automobiles, but they surveyed only 100 randomly selected households. If Lower-County Polling were also to sample over and over again (using simple random samples…

6. A study of report writing by psychologist is conducted. A scale that measures the intelligibility of psychologist English is devised. This scale, called an "index of confusion" is devised so that low scores indicate high readability. These data are obtained on articles randomly selected from psychology journals and from unpublished reports written in 2015. Unpublished reports 2.39 Journals 1.79 1.75 1.67 1.65 2.51 2.86 2.14 1.87 1.75 1.94 2.56 2.29 2.49 1.62 2.06 1.33 2.36 2.58 2.33 1.96 1.69 1.70 2.62 2.41 1.94 a. Test the appropriate hypotheses. b. Does there appear to be a difference between u, and u, ? Explain.