Descriptive Statistics

• What is the term for the data collected in psychological investigations?

  Raw data
• What do descriptive statistics summarize?

  Features of a quantitative data set
• What are the two main types of descriptive statistics?

  Measures of central tendency and dispersion
• What are measures of central tendency?

  • Mean
  • Median
  • Mode
• What are measures of dispersion?

  • Range
  • Standard deviation
• What is the mode in a data set?

  The most frequent score
• What does it mean if a data set is bimodal?

  It has two modes
• Why is the mode useful for discrete numbers?

  It avoids issues with outliers
• What is a criticism of the mode in small data sets?

  It may have multiple modes or none
• How is the median calculated?

  Order values and find the middle
• What is a positive aspect of the median?

  Not affected by extreme outliers
• What is a criticism of the median?

  Not all raw scores are used
• How is the mean calculated?

  Add all scores and divide by total
• What is a positive aspect of the mean?

  Uses all raw data in calculation
• What is a criticism of the mean?

  It can be distorted by extreme values
• Why might a CEO choose to state the mean salary?

  To present the company in a positive light
• What are the strengths and weaknesses of the mode?

  Strengths:

  • Simple to calculate
  • Useful for discrete data

  
  

  Weaknesses:

  • May have multiple modes
  • Not all values included
• What are the strengths and weaknesses of the median?

  Strengths:

  • Not affected by outliers
  • Easy to calculate

  
  

  Weaknesses:

  • Not all raw scores used
• What are the strengths and weaknesses of the mean?

  Strengths:

  • Uses all data
  • Sensitive to changes

  
  

  Weaknesses:

  • Affected by extreme values
• What is the range in a data set?

  Difference between largest and smallest values
• How is the range calculated?

  Subtract smallest value from largest
• What is a criticism of the range?

  Extreme scores distort its value
• What does the standard deviation indicate?

  How spread out scores are around the mean
• What is a positive aspect of the standard deviation?

  Includes all values in calculation
• What is a criticism of the standard deviation?

  Distorted by extreme values
• What is the formula to calculate percentages?

  Part divided by whole times 100
• What is a common way to express percentages?

  As a fraction or decimal
• How do you calculate the percentage of a subgroup?

  Convert fraction to decimal, then multiply
• How do you calculate percentage change?

  New number minus old number, then divide
• What is the percentage change for A-level students?

  21.7%
• What is the percentage change for B-tech students?

  -29.9%
• What are the types of correlations in statistics?

  • Positive correlation
  • Negative correlation
  • Zero correlation
• What is the correlation coefficient?

  A numerical measure of correlation strength
• What are the benefits of using descriptive statistics?

  • Summarizes large data sets
  • Provides insights into data trends
  • Aids in data interpretation
• How can descriptive statistics be misused?

  • Selective reporting of data
  • Misrepresentation of averages
  • Ignoring context of data