Psychology and Statistics

1. Psychology and Statistics Marshmallows!!! The Marshmallow Test

2. Descriptive statistics • describe or summarize a set of data • Two types • Measures of Central Tendency • Measures of Variance

3. 3 Measures of Central Tendency • Mean • Median • Mode

4. Measures of Central Tendency • Mean • Sum of a set of scores divided by the number of scores. Average score • Most used tendency

5. Measures of Central Tendency • Mean Weakness: Sensitive to extreme scores 10 students 9 get 90 1 gets 0 Mean: 81

6. Measures of Central Tendency • Median • Score that divides a frequency distribution exactly in half • 1, 3, 5, 7, 9, 11, 14 • 7

7. Measures of Central Tendency • Median Strength: Helps eliminate the effects of extreme scores 0,90,90,90,90,90,90,90,90,90 90

8. Find the Median • 3, 3, 3, 4, 4, 5 • Middle Numbers • Calculate the mean • 3.5

9. Measures of Central Tendency • Mode • Most frequently occurring score in a distribution • 1, 3, 5, 5, 7 , 8, 10 • 5

10. Measures of Variance • Simplest • Range • distance between the highest score and the lowest score • Tells how spread out my distribution is overall • Sensitive to extremes

11. Measure of Variance • Standard deviation • Most widely used • Tells us how much each score compares to the mean • Are scores close to the mean or more spread out? • Calculated by comparing each score to the mean • Larger the standard deviation – more spread out • Smaller the standard deviation – more clustered around the mean

12. Measure of Variance • Normal distribution • Forms a bell-shaped curve • Mean, mode, and median all at center • Crash Course

13. Researchers want to investigate the stereotype that women talk more than men. They outfit a large sample of college students with recording devices that automatically record them at random intervals throughout the day. The recorders collect a sample from each individual for the researchers to compare. • IV: • DV:

14. Cognitive psychologists wonder what kind of diagrams are easiest for people to remember. • IV: • DV: • Physiological psychologists wonder about the relationship between the intake of wine and emotional reactions to frightening stimuli. • IV: • DV:

15. Comparative psychologist study whether a young monkey will prefer to spend time with a pretend monkey made of wire that also provides milk or a pretend monkey that is covered with cloth but provides no milk. • IV: • DV:

16. An organizational psychologist test to see if wearing name tags make the employees happier with their work. • IV: • DV: • Developmental psychologists want to know if exposing children to public television improves their reading skills. • IV • DV