Statistics

Write down the number of pennies I can drop

into the cup at the front of the room without spilling any water.

Intuition vs. Empiricism•Empiricism emphasizes the role of experience and evidence .•This is your fact finding perspective. Give me proof, evidence.

•Intuition- understanding without apparent effort, quick and ready insight seemingly independent of previous experiences or empirical knowledge. (gut feeling)

Would anyone like to volunteer to win

some money?

Let’s Test This Statistical Strategy!

Class Wide Data Gathering Demo

1 student is subject1 student is

experimenter

Video clip

Descriptive vs. Inferential

• Descriptive– Summarizes a set of data,

makes it easy to interpret.

– %, averages

– r = correlation coefficient

– Standard Deviation

• Inferential– Allows us to make

decisions or reach conclusions about data.

– Statistically Significant or Chance? (p < .05)

– The probability of an event occurring by chance is less than 5%.

Measures of Central Tendency• Mode- most frequent• Median- middle most• Mean- average of set scores• Frequency distributions-(organized list)

» Can be misleading, know which measure of average is being used.

Positive/Negative Skew ?

Measures of Variability

• Range- difference in high/low

• Standard Deviation- square root of variance (measure of variance from the mean)– Packed together or dispersed?

Using Standard Deviation to your Advantage!Top 10 Rushing Leaders (2000)

Ranked Order of Rushers

• Who is the most consistent?– Davis

• Who is the most erratic?– Dillon

Correlations (Co-relation)

• r = -1.0 (strong negative correlation)↑↓

• r = +1.0 (strong positive correlation)↑↑ or ↓↓

• 0 = No Correlation

• Correlation coefficients help us determine the direction and strength of a relationship.

• Correlation does NOT imply causation!!

• Correlations may be used to predict!

Identify each of the scatter plots.r = -.99 r = -.7 r = 0 r = -.3 r = .5 r = .9

Scatter Plot A Scatter Plot B Scatter Plot C

Scatter Plot D Scatter Plot E Scatter Plot F