PSYCH501 Module 1

  1. study population
    clearly defined collection of people, animals, plants, or objects; usually a specific group of people
  2. response variable
    the measurement of the attribute of interest
  3. ratio scale
    • measurement with the following properties:
    • 0 represents comple absence
    • ratio of any two scores correctly describes ratio of attribute quantites
    • difference between two scores correctly describes difference in attribute quantities
  4. interval scale
    • measurement with the following properties:
    • 0 does not represent complete absence
    • ratio of any two scores does not correctly describe ratio of attribute quantites
    • difference between two scores correctly describes difference in attribute quantities
  5. quantitative measurement
    ratio or interval scale measurement
  6. population parameter
    single unknown numeric value that describes the measurements that could have been assigned to all N people in a specific study population
  7. population mean
    an unknown value; the average of all N scores that could have been assigned to all N people in a study population
  8. random sample
    a set of a study population of size n, selected in such a way that any set of size n has an equal chance of being selected
  9. sample mean
    an estimate of µ; the average of all scores from the sample
  10. standard error
    • Image Upload 2
    • value that numerically describes the accuracy of a parameter estimate
  11. sample variance
    • Image Upload 4
    • describes the variability of the scores in the sample
  12. sample standard deviation
    • Image Upload 6
    • estimate of ơ; describes the variability of the scores in a sample
  13. confidence interval
    range of values that is believed to contain an unknown population parameter value with some specified degree of confidence
  14. null hypothesis
    H0: µ = h; states that the mean is equal to some specified value
  15. three-decision rule
    1a general hypothesis testing procedure in which one of the following decisions will be made: 1) accept H1, 2) accept H2, 3) fail to reject H0
  16. test statistic
    a value obtained from a t-test, used to determine whether or not to reject the null hypothesis
  17. one-sample t-test
    a test of the null hypothesis applied to a single population mean
  18. p-value
    a number determined by the test statistic; small p-values correspond to high test statistics and the researcher may reject the null hypothesis if p is less than α (usually .05)
  19. significance testing
    an alternative to hypothesis testing where results are declared "significant" if the p-value is less than some set value, usually .05
  20. histogram
    graph that visually displays a set of quantitative scores; displays the number of scores falling into specified ranges of scores
  21. normal curve
    • a curve in which:
    • half of the scores are above the mean and half are below (the mean, median, and mode are identical)
    • 68% of scores are within 1 standard deviation above or below the mean
    • 95% of scores are within 2 standard deviations above or below the mean
    • 99.7% of scores are within 3 standard deviations above or below the mean
  22. sampling distribution
    the set of all possible sample means obtained from all possible samples in the study population
  23. central limit theorem
    states that if the sample size is sufficiently larg, the distribution of the sample means will be closely approximated by a normal distribution
  24. unbiased estimate
    an estimate which overestimates the population parameter with about the same tendency as it underestimates the population parameter
  25. probability
    a number on a 0 to 1 scale that describes the likelihood of an event
  26. classical definition of probability
    the proportion of all possible events that are of the type in question
  27. power
    the probability of rejecting the null hypothesis
  28. type I error
    rejecting the null hypothesis when, in reality, µ = h
  29. prediction interval
    • Image Upload 8
    • a range of plausible scores for one randomly selected person
  30. planning value
    a value obtained from experts, preliminary studies, or previoiusly published research
  31. target population
    a population of interest to the researcher from which the study population is taken
  32. convenience sampling
    nonrandom samlle obtained for ease or availability
  33. random sampling assumption
    requires the sample to be a random sample from the study population or some hypothetical population
  34. independence assumption
    requires that the responses from each participant in the study be independent of each other
  35. normality assumption
    requires that the scores in the study population have approximately a normal distribution
  36. coefficient of skewness
    numerically describes the skewness of a set of scores; zero if scores are symmetrical, positive if scores are skewed right, negative if scores are skewed left
  37. coefficient of kurtosis
    describes to degree to which a distribution is more less peaked than the normal distribution; equal to 3 in normal curve (coefficient - 3 = excess kurtosis), excess kurtosis > 0 is highly peaked with long tails, excess kurtosis < 0 is lower peaked with short tails
  38. data transformation
    scores are all manipulated mathematically to reduce skewness and kurtosis
Card Set
PSYCH501 Module 1
definitions for module 1