Statistics & Data Analysis Research

MM570 Applied Statistics for Psychology

Unit 6 Project: Descriptive Statistics

1. Recall that the dataset, Stat_grades.sav, contains data for a sample of 105 statistics students. One of the variables in this dataset is called, lowup (Lower or Upper Division). This variable is either “1” for “Lower Division” (which includes first years and sophomores), or “2” for “Upper Division” (which includes juniors and seniors). The Instructor who created the Stat_Grades,.sav dataset believes that there is a significant difference in class performance between Lower Division and Upper Division students. Using the appropriate statistical test, methods, and evaluations, determine if attending Lower or Upper Divisionmade a significant difference in the Final Course Percent(percent) for students. Be sure to include each step of the process, any SPSS results used, an interpretation of the results, and the final conclusions.

(a) What is the hypothesis being tested here?

(b) What are Ho and Ha?

(c) What is the name of the test you will run? Run the appropriate SPSS test and include the SPSS output here.

(d) What are the results of the test? What is the p-value and is it larger or smaller than the alpha value – show your work and explain the result.

(e) Write a conclusion for the above in plain English so that any person could understand. What can you say about the review and its effect on total points and student overall performance?

2. Based on manyyears of past classes and experience, the Instructor for the students in the Stat_Grades.savdataset has determined that a successful mean value for Final Course Percentage (percent) is 75. Does the Final Course Percent for the students inStat_Grades.sav differ significantly from the known success value of 75? Use and include the appropriate statistical test, methods, and evaluations. Be sure to include each step of the process, any SPSS results used, an interpretation of the results, and final conclusions.

(a) What is the hypothesis being tested here?

(b) What are Ho and Ha?

(c) What is the name of the test you will run? Run the appropriate SPSS test and include the SPSS output here.

(d) What are the results of the test? What is the p-value? Compare the p value to alpha and note the result.

(e) Explain the conclusion in plain English so that any person could understand. Did the students in Stat_Grades.sav do significantly differently than the population mean of 75? How did they do and what did you find. Explain.

3. Using the Stat_Grades.sav dataset, compare Quiz 3 andQuiz 4 and determine if there is a statistically significant difference in the average student performance between these two quizzes. Use and include the appropriate statistical test, methods, and evaluations. Be sure to include each step of the process, any SPSS results used, an interpretation of the results, and final conclusions.

(a) What is the hypothesis being tested here?

(b) What are Ho and Ha?

(c) What is the name of the test you will run? Run the appropriate SPSS test and include the SPSS output here.

(d) What are the results of the test? What is the p-value? Compare the p value to alpha and note the result.

(e) Explain the result and conclusion of the test in plain English so that any person could understand.

4. Use the following SPSS output to answer these questions.The hypothesis here is: “Is there a significant difference in mean GPA between the students in Stat_Grades.sav (called Previous GPA) and the known mean population GPA value (for all students) of 3.00?”

(a) What is Ho and Ha?

(b) What t-test is being used?

(c) What is the p value?

(d) Using alpha at .05, what is the result of this test?

(e) Write the full conclusion for this test in plain Englishso anyone can understand.

(f) How many students are in this sample of data? Is the mean GPA for the sample of students different than for the known population? Is it significantly different? What does it mean to be significantly different (versus just different)?