Psychology and Statistics Marshmallows The Marshmallow Test Descriptive

Psychology and Statistics Marshmallows!!! The Marshmallow Test

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

3 Measures of Central Tendency • Mean • Median • Mode

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

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

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

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

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

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

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

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

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

• 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:

• 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:

• 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:

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