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WHS AP Psychology. Descriptive Statistics: Scales of Measurement Measures of Central Tendency. Essential Questions. EQ 1-5: How do psychologists draw appropriate conclusions about behavior from research?. Statistical Reasoning.
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WHSAP Psychology Descriptive Statistics:Scales of MeasurementMeasures of Central Tendency
Essential Questions • EQ 1-5: How do psychologists draw appropriate conclusions about behavior from research?
Statistical Reasoning Statistical procedures analyze and interpret data and let us see what the unaided eye misses. Composition of ethnicity in urban locales
Describing Data Meaningful description of data is important in research. Misrepresentation can lead to incorrect conclusions.
Gender • Operational definition is simply either male or female. • This is nominal or naming scale • Men are in category 1, and women are in category 2. • Other Examples: Jersey Numbers, Eye Color, Shirt Color • All you are allowed to do is name.
Attraction • Many of you used a Likert Scale (Not attracted, Somewhat Attracted, Very Attracted.) • This is an Ordinal or ordering scale • You rank things • Does not tell you how much more attracted you are. • Other Examples: Where you finish in a race, if a person ranks their favorite ice cream • All you can do is greater than or less than operations.
1 2 3 4
Personality or Intelligence • Administer a personality or intelligence test • This is an Interval scale • Tells us how many equal size units one thing lies above or below another. • No zero, so you can’t tell how many times bigger, smaller etc. • Other Examples: Temperature • All you can do is add and subtract
Mastery of Unit 1 • Our Unit One Exam • This is a Ratio Scale • Equal distance between values and a zero. • Other Examples: Height, Weight, Snowfall • You can multiply and Divide
Avatar (2009)$2,768,562,778 • Titanic (1997)$1,835,300,000 • The Lord of the Rings: The Return of the King (2003)$1,129,219,252 • Pirates of the Caribbean: Dead Man's Chest (2006)$1,060,332,6285. • Toy Story 3 (2010)$1,031,376,037 • Alice in Wonderland (2010)$1,023,285,206 • The Dark Knight (2008)$1,001,921,825 • Harry Potter and the Sorcerer's Stone (2001)$968,657,891 • Pirates of the Caribbean: At World's End (2007)$958,404,152 • Harry Potter and the Order of the Phoenix (2007) $937,000,866
Scale Level Scale of Measurement Scale Qualities Example(s) 4 Ratio Magnitude Equal Intervals Absolute Zero Age, Height, Weight, Percentage 3 Interval Magnitude Equal Intervals Temperature 2 Ordinal Magnitude Likert Scale(Agree/Disagree) Anything rank ordered 1 Nominal None Names, Lists of words, Jersey Numbers
Central Tendency • Tendency of scores to congregate around some middle variable • A measure of central tendency identifies what is average or typical in a data set
Measures of Central Tendency Mode:The most frequently occurring score in a distribution. Mean:The arithmetic average of scores in a distribution obtained by adding the scores and then dividing by their number. Median:The middle score in a rank-ordered distribution.
But the meandoesn’t work in a skewed distribution The Median is much better
Negatively Skewed Positively Skewed
Essential Questions • EQ 1-5: How do psychologists draw appropriate conclusions about behavior from research?