Observational studies can reveal only association, whereas designed experiments can help establish inference. inference. independence. correlation. causation.

A researcher gathered a sample of participants who volunteered for a studying of phobias. She measured anxiety level of participants as they viewed photos of spiders and again when they viewed puppies. Which statistical test is appropriate for this study and why?

Bullying,” according to noted expert Dan Olweus, “poisons the educational environment and affects the learning of every child.” Bullying and victimization are evident as early as preschool, with the problem peaking in middle school. Suppose you are interested in the emotional well-being of not only the victims but also bystanders, bullies, and those who bully but who are also victims (bully-victims). You decide to measure anxiety in a group of bullies and a group of victims using an 18-item, 5-point anxiety scale. Assume scores on the anxiety scale are normally distributed and that the variances of the anxiety scores are the same among bullies and victims. The group of 23 bullies scored an average of 40.1 with a sample standard deviation of 10 on the anxiety scale. The group of 28 victims scored an average of 46.8 with a sample standard deviation of 11 on the same scale. You do not have any presupposed assumptions about whether bullies or victims will be more anxious, so you formulate…

Report an appropriate hypothesis test for a positive linear relationship and use a 5% significance level. Explain the potential error in words, in context. In the answer options below I have used the phrase “a certain relationship” because I don’t want to give away exactly what type of relationship it is. Group of answer choices We would be accepting that there was a certain relationship between Sale amount and Tip when actually there wasn’t. We would not be accepting that there was a certain relationship between Sale amount and Tip when indeed there wasn’t. We would not be accepting that there was a certain relationship between Sale amount and Tip when actually there was. We would be accepting that there was a certain relationship between Sale amount and Tip when indeed there was.

Correlation and causation are the same concept. O True False

Using SPSS, analyze the relationship between respondents’ marital status (MARITAL) and whether they believe it is alright for a couple to live together without intending to get married (COHABOK) using crosstabulation.  Which marital status category is most disapproving of nonmarital cohabitation?  Which marital status category is most approving of nonmarital cohabitation?  Is the relationship between marital status and attitude toward nonmarital cohabitation statistically significant at the .05 level?  Compute and interpret an appropriate measure of association for this relationship.

Tips It’s commonly believed that people use tips toreward good service. A researcher for the hospitalityindustry examined tips and ratings of service qualityfrom 2645 dining parties at 21 different restaurants. The correlation between ratings of service and tip percent-ages was 0.11. (M. Lynn and M. McCall, “Gratitude and Gratuity.” Journal of Socio-Economics 29: 203–214)a) Describe the relationship between Quality of Serviceand Tip Size.b) Find and interpret the value of R2 in this context.

If a teacher wants to assess whether positive feedback impacts test performance and she assesses test performance at the beginning and end of a semester in a single group of students, the most appropriate statistical test would be: point biserial correlation independent samples t-test correlated groups t-test pearson's r correlation

In a study examining the relation of math ability to the belief that math ability was innate, the belief was considered the predictor variable. The researcher hopes to find a correlation between the participants’ math ability and their belief that math ability is innate.  The scores for the three participants are shown below.   The group that believed that math is NOT innate scored 66, 70, 50.   The group that believed that math IS innate scored 7, 4,10.                                Calculate, by hand, the correlation between these two variables.  Is it positive or negative and is it a strong correlation?

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