Statistics and Probability

• Sample Space


  Set of possible outcomes; S
• Continuous Random Variable


  Random variable...that take decimal or fraction; represent measurable amounts
• Standard Score / Z Score


  Distance between a given value X and the mean
• Variance and SD


  • Describes the dispersion or the variability of the distribution
• Normal Curve / Bell Curve


  Represents the probability density function
• Random Variable


  Function that associates a numerical value; X
• Parameter


  Describes an entire population (e.g., 45% of shs students are male)
• Normal Distribution


  Where most of the scores are closer to the mean
• Random Experiment


  Experiment that can be repeated numerous times; result must be independent of one another
• Probability Distribution of a Discrete Random Variable


  A list...or a formula of probabilities associated with each of its possible values
• Stratified Random Sampling


  • Selecting a simple random sample...subpopulation
  • Stratum - subpopulation (plural: strata)
• Multistage Sampling


  Two or more probability techniques are combined; sampling within the sample
• Cluster Sampling


  Population is divided into separate groups called clusters
• Population


  Where members have something in common; total set of observations
• Carl Friedrich Gauss: 'Named the Gaussian Curve a.k.a the normal curve'
• Empirical Rule


  States that 68.26% of the scores fall within one standard deviation away from the mean, 95.44% of the scores fall within two standard deviations away from the mean, and 99.74% of the scores fall within three standard deviations away from the mean.
• Statistic


  Describes only the sample (e.g., 2 out of 100)
• Discrete Random Variable


  Random variable with a finite...can be counted; represent counts
• Normal Random Variable


  Continuous random variable of normal distribution
• Outcome


  Result of a random experiment
• Outliers


  • Scores that more than two sd away from the mean
  • Extreme Outliers - scores that more than three sd away from the mean
• Standard Normal Distribution


  Mean = 0, sd = 1
• Sample


  Smaller group or subset of the population
• Simple Random Sampling


  Each member...has an equal chance of being chosen
• 1. in-k Systematic Random Sampling


  Random selection of one of the first k elements in an ordered population...systematic selection of every kth element
• domain

  sample space
• range

  set of real numbers
• standard deviation

  the square root of the variance
• extreme outliers

  sores that are more than 3 standard deviation away from the mean
• stratum

  subpopulation (plural: strata)
• multistage sampling

  two or more probability techniques are combined; sampling within the sample