Question

For my PSY 240 course, I implemented a new practice of bringing in guest speakers at various stages of life. The goal is to have students observe real-life examples of developmental stages and thus have higher final course percentage scores as a result.

In order to see if this new element was helpful to students, I compared results from the final percentage scores of my current class to the existing pool of past final percentage scores from all my previous sections of PSY 240 prior to implementing the guest speaker sessions. In other words, the new class with the guest speakers 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 PSY 240 final percentage scores has a mean (μ) of 85 and standard deviation (σ) of 7 points. The new class of 36 students had a mean (M) final percentage score of 87 points. I conducted a hypothesis test to see if the new class would have significantly differently final percentage scores from the population of past students. I was interested in any type of “difference,” whether it’s an increase or a decrease in final percentage score. The significance level for my Z test was set at α = .05.

a)   Identify the dependent variable for this study (1 points)

b)   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 non-directional

c)   Calculate standard error (SE, which is the standard deviation of the sampling distribution) (2 points total: 1 for process/work, 1 for result)

d)   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)

e)   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)

   MAY I PLEASE GET A STEP BY STEP ON HOW TO FIGURE OUT THESE PROBLEMS. Thank you to whoever helps!

Answer 1

Answer a)

In this case, dependent variable is percentage score

Answer b)

Null and Alternative Hypotheses

Ho: μ = 85 (The new class score is have significantly different final percentage scores from the population of past students)
Ha: μ ≠ 85 The new class score is do not have significantly different final percentage scores from the population of past students)

Answer c)

SE = σ/SQRT(n)

Here, n = 36 and σ = 7

SE = 7/SQRT(36) = 7/6

SE = 1.1667

Answer d)

Test Statistics

Answer e)

It is a two-tailed test because here we are only interested in knowing whether there is difference in final percentage score between new class and population of past students. We are not interest in knowing whether difference is positive or negative.