Question: for my psy230 course i started a new practice of...
For my PSY230 course, I started a new practice of offering extra credit for making an appointment with the Statistics and Methods Lab. The goal is to help students feel more positive toward statistics through one-on-one assistance and therefore feel more comfortable in the course.
In order to see if this new element was effective, I compared results from a statistics attitude survey given to my current class to the existing pool of past statistics attitude surveys from all my previous sections of PSY230 prior to implementing SAM Lab extra credit. In other words, the new class with the SAM Lab extra credit is my sample, which will be compared to the population of all of my past students.
According to my records, the population of all past statistics attitude surveys have a mean (μ) survey score of 71 points and standard deviation (σ) of 6 points. The new class of 64 students had a mean (M) survey score of 73 points. I conducted a hypothesis test to see if the new class would have significantly higher attitude scores from the population of past students. My review of the previous literature showed interventions such as this to have a positive effect, and so I was interested in whether there is an improvement in attitude score. The significance level for my Z test was set at α= .05.
- Identify the dependent variable for this study (1 points)
- State your null hypothesis and alternative hypothesis using both words and statistical notation (4 points: 1 for each notation, 1 for each written hypotheses)
Hint: The hypotheses should be directional
- Calculate standard error (SE, which is the standard deviation of the sampling distribution) (2 points total: 1 for process/work, 1 for result)
- Calculate the Z statistic (which indicates where our sample mean is located on the sampling distribution) (2 points total: 1 for process/work, 1 for result)
- Specify whether the hypothesis test should be a two-tailed or a one-tailed test, and explain the rationale for the choice. (2 points total: 1 for chosen test, 1 for rationale)
- Determine the critical value for Z (1 point)
- Comparison of obtained Z and critical Z and then make a decision about the result of the hypothesis test: Explicitly states “reject” or “fail to reject” the null hypothesis (2 points: 1 for comparing the correct numbers and saying which one is more “extreme”; 1 for making the decision about null hypothesis.)
- Write a 1-2 sentences to conclude the results (you can simply restate the accepted hypothesis or explain it in another way) (1 point)
- Calculate the raw effect size and the standardized effect size for this test. (4 points total: 2 points for each measure: 1 for process/work, 1 for result)
- In order to perform a more rigorous test, I could also set up a non-directional research hypothesis. What would the written hypotheses and the notations be? (4 points total: 1 for each notation, 1 for each written hypotheses)
- Using the alpha level α= .05, determine the critical Z value for the non-directional hypothesis. (1 point)
- In this statistical test, how high does the mean statistics attitudinal survey score from the new class have to be, at least, to be considered “significantly” higher than the pool of past statistics attitudinal survey scores?
Hint: In other words, when does the calculated Z equal the critical Z? What needs to be the sample mean for that to happen?(2 points total: 1 for answer, 1 for formula/work)