Exam 12: Bivariate Statistics and Statistical Inference
Which of the following correlation coefficients is the strongest?
A
The null hypothesis is a statement that there is:
A
Several difference p-values are listed below; identify which one is considered statistically significant according to typical standards in social work research, then briefly discuss what this value actually means.
.75
.50
.03
.21
.13
In social work research, as in many other fields, a p-value of 0.05 or lower is typically considered the threshold for statistical significance. This standard is widely adopted, although it is somewhat arbitrary and other thresholds (like 0.01 or 0.10) can be used depending on the context and the level of confidence a researcher wishes to have in their results.
Given the p-values listed: .75, .50, .03, .21, .13, the one that is considered statistically significant according to typical standards is:
.03
This p-value of 0.03 means that there is a 3% probability that the observed data, or something more extreme, could have occurred under the null hypothesis. In other words, if there truly were no effect or no difference (as the null hypothesis states), there would only be a 3% chance of obtaining the observed results or results that are more extreme purely due to random chance.
A statistically significant result suggests that the researcher can reject the null hypothesis with a reasonable level of confidence, typically 95% confidence when using the 0.05 threshold. In this case, with a p-value of 0.03, the researcher can be 97% confident that the results are not due to random chance, and thus, there is likely a real effect or difference present.
It is important to note that statistical significance does not necessarily imply practical significance or importance. A result can be statistically significant but still be of little practical value if the effect size is very small. Additionally, statistical significance does not confirm causation; it merely suggests that there is evidence to reject the null hypothesis of no effect or no difference.
Research designs that involve randomization are rare in social work because of:
A social worker conducts a research study and finds that two variables have a Pearson's r of -.45. What does this value indicate regarding the strength and the direction of the relationship between these two values?
A straight line drawn though the points on a scatter plot so that one half of the points are above the line and one half are below it is called:
What involves calculating the probability of committing a Type II error based on the type of test, the sample size, and an estimate of the strength of the relationship?
Which involves making a calculated decision based on the results of an observation by employing mathematical calculation of the odds?
Develop a simple research question appropriate for hypothesis testing; state the null hypothesis, a nondirectional or two-tailed hypothesis; and a directional or one-tailed hypothesis.
A professor wants to know if students learn as well taking an online course versus a face-to-face course. The online class has 21 students while the face-to-face class has 16 students. The professor wants to know if the averages between the same final exams are significantly different. What statistic should be used?
Using the following data, construct a cross tabulation table comparing BSW students and MSW students in terms of their value of gerontology in social work education (value or do not value). Simple addition and subtraction is necessary.
Total BSW students = 125
Total MSW students = 75
Frequency/percent of BSW students who value gerontology = 80(.64)
Frequency/percent of MSW students who value gerontology = 25(.33)
Briefly describe when parametric statistics are appropriate and when nonparametric statistics are appropriate.
Which statistical test of significance would be appropriate for hypothesis testing with the social work student data presented above?
Explain the relationship between statistical significance testing and probability.
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