1. Welcome to MM570 Psychological Statistics Unit 2 PowerPoint Guide Seminar Guide and Unit 2 Project Linda Des Jardines

2. Instructor Contact Information Instructor: Dr. Linda Des Jardines Email: Email is a great way to reach me fast! LDesJardines@Kaplan.edu I check my email everyday Always include all information in email – especially your full name and question Office hours: Sunday, 4:00-5:00 PM ET If you lose Internet access, be sure to: 1)get it back as soon as you can 2)have a back up plan, such as work after hours, an internet café, public library, friend or neighbor, etc.

3. Numerical Measures (also called summary or descriptive statistics) Quick Overview: Note: Chapter 2 in the textbook has excellent and graphical examples of each: Mean – the average Median – the center of an ordered set of numbers Mode – the most frequently occurring value in a dataset Variance – a measure of the square of the average amount a dataset varies from its mean Standard Deviation – the square root of the variance. Range – the largest value minus the smallest value Min – the smallest value Max – the largest value

4. Measures of Central Tendency Sum of all the scores divided by the number of scores Mean of 7,8,8,7,3,1,6,9,3,8 ΣX = 7+8+8+7+3+1+6+9+3+8 = 60 N = 10 Mean = 60/10 = 6

5. The Mean Mean of the distribution of the number of dreams during a week for 10 students.

6. Measures of Central Tendency- the Mode Most common single number in a distribution Mode of 7,8,8,7,3,1,6,9,3,8 = 8 Measure of central tendency for nominal variables

7. The Mode The mode is the high point in a distribution’s histogram, using the example of the number of dreams during a week for 10 students.

8. Measure of Central Tendency- the Median The middle score when all scores are arranged from lowest to highest Median of 7,8,8,7,3,1,6,9,3,8 1 3 3 6 7 7 8 8 8 9 median Median is the average (mean) of the 5 th and 6 th scores, so the median is 7

9. What’s the Difference? When do we use each one? Mean is appropriate when we have ratio data and the data has no outliers Median is best used when there are outliers. Why? Mode can be used for qualitative or quantitative data.

10. Example: Michael Jordan graduated with a degree in geography from UNC. If the school claims their geography majors have the highest average beginning salaries of all geography majors in the country are they lying?

11. Example cont. If Michael made $20,000,000 his first year playing in the NBA and his 4 classmates got first year jobs in geography, let’s find the mean: 20,000,000 20,000 21,000 22,000 20,000

12. Example cont. The mean is $4,016,600. hmmm The median is $20,000. Which measure is more appropriate to describe the beginning salaries?

13. Measures of Variability- the Variance

14. Standard Deviation Most common way of describing the spread of a group of scores Steps for computing the standard deviation: 1.Figure the variance 2.Take the square root We use SPSS instead!

15. What is Variance? Variance is a measure of the spread of our data values. Let’s compare deliver times for two pizza places on a Tuesday night: Pizza Place A Pizza Place B 24 40 23 27 22 15 23 10

16. Variance (cont.) To find the average delivery time for each Pizza Place, we can add all the times up and divide each by 4. The mean delivery time for both places is 23 minutes. However, the times for Pizza Place A are much more consistent than those of Pizza Place B. For the first pizza place, the times are all pretty much around the average of 23. However, the second pizza place had times that ranged from 10 minutes to 40 minutes- quite a spread!

17. Variance cont. In many areas of our life, we value consistency. We want to be able to depend on what companies tell us – how long will this battery last, how long will I be on hold? The more consistent the values, the more we can rely on them. Statistics uses the standard deviation extensively. After calculating the variance, the standard deviation can be found by taking the square root of the variance.

18. Appropriate Numerical Measures Certain numerical measures can be more appropriate to describe certain variables. Example: Variable “Religion” 1 = None Specified 2 = Buddhist 3 = Hindu 4 = Islamic 5 = Jewish 6 = Christian Let’s create this variable in SPSS using Variable View.

19. The Religion Data Here, all the Religion data is in SPSS. Remember that “1” is “none specified”, “2” is “Buddhist”, and so on. Which numerical measure best describes this data? What type of data is this? This is nominal. It is category data that has no order. 6 is NOT less than 1. This is also qualitative data as it describes a quality – Religion. The number categories are not real quantities. If we add “2” (Buddhist”) + “3” (Hindu) this does NOT equal “5” (Jewish). These numbers are NOT numerical values, they are just categories. Do “mean” or “median” give information here? NO! Why? How about “mode”? Yes! Why?

20. The Most Appropriate Graph Which graph should be used to represent the Religion data? There are many options. One good choice for category data is a bar graph. What does this graph tell you?

21. Part III Getting Started with the Unit 2 Project Hint: It is a great idea to start the Unit 2 Project during Unit 1. This will give you a lot more time!! Projects can take time – always plan ahead and give yourself extra time

22. When you open the Statistics Class data file in SPSS (called Stat_Grades.sav) – this is what it looks like. You will use this dataset for all four class projects.

23. Finding Project Assignments and Project Data in Doc Sharing You can find the Stat_Grades.sav project dataset and project assginments in Doc Sharing under the Graded-Projects category

24. Hints for Completing Projects with Success: 1) Give yourself enough time. Start early! 2) Read each question carefully and be sure to answer all portions of the question. 3) When asked to describe or explain – always use proper paragraph form, correct grammar, correct spelling, and complete sentences. 4) Avoid being too brief. Pretend you are explaining your results to a person who is not very knowledgeable about statistics.

25. Part IV Examples in SPSS

26. Understanding the Variables in the dataset (Stat_Grades.sav) using Variable View

27. Using Variable View to learn about variables. Here, we can click on Year in School under “Values” and a box pops up to show us that there are four categories: 1 = First year 2 = Sophomore 3 = Junior 4 = Senior

28. Using SPSS to find Summary Statistics (also called descriptive numerical measures) Step 1

29. Step 2 in SPSS: Choose the variable(s) you would like to get descriptive or summary statistics for: You can click on any variable from the left list and then you can use the blue arrow to move that variable into the right “Variable(s) area. Only variables that you choose will be part of your analysis. Here, I will analyze “Gender” and Quiz 1 Points”

30. Step 3: Choose Statistics and then select the statistics you want SPSS to calculate.

31. Step 4: SPSS Results SPSS can generate many types of results. Here are results for Mean, Median, Mode, Std. Deviation, Variance, Range, Minimum, and Maximum.

32. Example 2: Making Graphs in SPSS Step 1: Here I chose a Pie Chart.

33. Example 2: Making Graphs in SPSS Step 2: SPSS uses “drag and drop” to choose and create graphs. Choose the Graph type. Drag it into the Gallery area.

34. Step 3: To create a graph for gender, drag the “Gender” variable to the x-axis. Drag and drop! Next, add Titles/Footnotes

35. Graph Result Note: You can double – click any graph in SPSS and edit the graph. This is also a good way to copy and paste the graph to Word.

36. Editing and Copying Graphs in SPSS Double-click any graph you make. Choose “Edit”

37. What if you want to look at summary statistics for all 5 quizzes in SPSS at the same time? No problem! Step 1: Analyze  Descriptive Statistics  Frequencies

38. Step 2: Using the blue arrow, move all 5 quizzes to the right side Variable(s) area at once. Then choose Statistics.

39. Results show all 5 quizzes in the same table. Nice and easy to compare this way.

40. Learning SPSS Takes Patience and Practice If at first you do not succeed…try try again Extra Resources and Examples for SPSS: 1)The Live Binder – contains videos and live examples. 2)The Green and Salkind SPSS Textbook Table of Contents: Lessons 1 – 6: Intro to SPSS Lessons 16A and 17A: Making Graphs