Interpreting and Communicating Data

Question 1

Best way to display data:

Answer 1

Clearly convey findings

Pay attention to y-axis

Question 2

How are data scores distributed?

Answer 2

View with frequency distribution- histogram

• indicates number of times each score is obtained in given category
• one way to show raw data

Question 3

What number best represents group performance?

Answer 3

Central tendency

• mode: most frequent
• median: middle score
• mean: avg. of scours

Dispersion

• std deviation: gets larger as spread of scores gets larger
• > can differ, even if same median and mean

Question 4

Types of frequency distribution

Answer 4

Normal (mean=median=mode, or nearly so)

• unimodal
• symmetrical
• scores cluster near midpoint

Bimodal
-scores cluster at two points in distribution

Truncates

• scores cut off at one end
• might be due to floor or ceiling effects

Skewed

• asymmetrical distribution
• more scores at one end
• positively (mean > mode)
• negatively (mean < mode)

Question 5

Display means or frequencies

Answer 5

• bargraphs/histograms

- line graphs (can indicate the type of function that best describes data)

Question 6

Monotonic

Answer 6

Function does not reverse direction

Question 7

Display scores for correlational data

Answer 7

Scatterplots

• each point represents data from one subject
• shows direction of relationship and dispersal

Question 8

Statistical significance

Answer 8

Probability there is an effect of IV on DV
Does not indicate size of effect
Does not indicate importance of effect

Question 9

Meta-analysis

Answer 9

Statistic technique
Combines results of many studies to evaluate effects of similar IVs
Data points used are means obtained in different studies

Question 10

Conducting meta-analysis

Answer 10

Identify IV and DV of interest
Locate all relevant studies examining these variables
Combine statistical stat across studies into meta-anakysis statistic
May show an effect even if all/most individual studies do not

Question 11

How researchers communicate results

Answer 11

Informal contact
Present results at scientific meetings
Publication in scientific journals

Question 12

Publication process

Answer 12

1. Select one journal, send editor paper
2. Peer review
3. Editor makes decision
4. Author decides: further research; revise and return; submit to another journal; give up

Steps 1-3 take 2-4 months