3rd Research methods

• What is a scattergram used for?


  To show a relationship between two variables
• What is the purpose of presenting data in an accessible way?


  To ensure that findings are easily understood by others
• What are the three commonly used graphs to display quantitative data?


  • Histogram
  • Bar Charts
  • Scattergrams
• What are the characteristics of a histogram?

  Columns are of equal width, touch each other, and show all intervals
• When is a histogram used?

  When presenting continuous data
• What distinguishes bar charts from histograms?


  Bar charts present non-continuous data and columns do not touch
• What does a scattergram indicate?


  The type and strength of the relationship between two variables
• What does the correlation coefficient range from?


  From +1 to -1
• What does a correlation coefficient of +1 indicate?


  A perfect positive correlation
• What is the mean in measures of central tendency?


  The average calculated by adding all scores and dividing by the total number of scores
• How is the median calculated?


  By ordering the data and finding the middle score
• What is the mode?


  The most frequently occurring score in a data set
• What are the advantages and disadvantages of the mean, median, and mode?


  Advantages:

  • Mean: Takes all scores into account
  • Median: Unaffected by outliers
  • Mode: Unaffected by outliers

  
  

  Disadvantages:

  • Mean: Can be distorted by extreme scores
  • Median: Not good with small data sets
  • Mode: Can be affected dramatically by one score
• What is a measure of dispersion?


  It indicates how much variability there is in a data set
• How is the range calculated?


  By subtracting the lowest score from the highest score
• What is the range for the data set 5,4,1,2,1,2,3,4,5,6,8,7,2?


  7
• What is the range for the data set 9, 11, 16, 4, 6, 17, 22, 35, 2, 12, 13?


  33
• What is the range for the data set 3, 4, 5, 8, 11, 14, 12, 16, 1, 9, 15, 17?


  16
• What does standard deviation measure?


  The spread of scores around the mean
• What does a large standard deviation indicate?


  Many data points are far away from the mean
• What does a small standard deviation indicate?


  Data points are closely clustered around the mean
• What does a standard deviation of zero indicate?


  All data values are the same with no variation
• What are the strengths and weaknesses of quantitative and qualitative data?


  Strengths of Quantitative Data:

  • Easier to analyze
  • Provides clear numerical results

  
  

  Weaknesses of Quantitative Data:

  • May miss detailed information

  
  

  Strengths of Qualitative Data:

  • Provides detailed information

  
  

  Weaknesses of Qualitative Data:

  • Harder to analyze
  • May require coding units
• What is primary data?


  Data obtained firsthand by the researcher
• What is secondary data?


  Data that has been collected by other individuals
• What are the strengths and weaknesses of primary and secondary data?

  Strengths of Primary Data:

  • Control over quality

  
  

  Weaknesses of Primary Data:

  • Lengthy and expensive

  
  

  Strengths of Secondary Data:

  • Easier to obtain
  • Time/cost effective

  
  

  Weaknesses of Secondary Data:

  • May not fit the needs of the study exactly
• What is a normal distribution?

  • A bell-shaped curve
  • Mean, median, and mode are at the midpoint
  • Many human characteristics are normally distributed
• What is a skewed distribution?


  • Scores are not distributed equally around the mean
  • Negative skew: most scores are high
  • Positive skew: most scores are low
• What is the purpose of statistical tests in psychology?


  To determine if results are due to chance or are statistically significant
• How is probability expressed in science?


  As a number between 0 and 1
• What does a probability of 0 mean?


  It means an event definitely will not happen
• What does a probability of 1 mean?


  It means an event definitely will happen
• How is probability calculated?


  Probability = number of particular outcomes / number of possible outcomes
• What is the generally accepted level of significance in psychology?


  5% (p=0.05)
• What does it mean if the probability of the null hypothesis is lower than the level of significance?


  It can be rejected
• What is a Type 1 error?


  Rejecting a null hypothesis when it should have been accepted
• What is a Type 2 error?


  Accepting a null hypothesis when it should have been rejected
• What is the likelihood of making a Type 1 error at a significance level of p=0.05?


  1 in 20 (5%)
• What factors determine which inferential test to use?


  1. Research aims
  2. Type of data
  3. Research design
• What type of data is nominal data?


  Data that falls into different categories