Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Psychological Statistics Chapter 1

Intro to Stats for the Behavioral Sciences

  • Login to see the comments

Psychological Statistics Chapter 1

  1. 1. Introduction to Statistics for the Behavioral Sciences
  2. 2. Statistics  It the practice or science of collecting and analyzing numerical data in large quantities, especially for the purpose of inferring proportions in a whole from those in a representative sample.
  3. 3. Statistics Branches of Statistics Descriptive -organizes, summarizes, and communicates a group of numerical observations. Inferential -uses sample data to make general estimates about the larger population.
  4. 4. Statistics • Observations drawn from a population of interest. It is described by a statistic. Sample • All possible observations about which we would like to know. It is described by a parameter. Population
  5. 5. Sampling Techniques  Random Sampling – every member of a population has an equal chance of being selected.  Systematic Sampling – taking the nth element from a given list.  Stratified Sampling – division according to categories  Cluster Sampling – the population is divided into clusters where samples are extracted.
  6. 6. Sampling Techniques  Non-random Sampling –recruitment of participants occur all of a sudden as the researcher may ought them to be useful despite of being unable to generalize the results found from such sample  Convenience Sampling – direct selection of participants until the desirable amount is reached by the researcher  Quota Sampling – similar to convenience sampling, but it ensures equal representativeness.  Snowball Sampling – a sampling based on recommendations.  Purposive Sampling – a sampling based on the knowledge of a given population and the research objective.  Self-selected Sampling – a sampling based on the desire of the people to identify themselves with the population being studied.
  7. 7. Variables  It is any observation of a physical, attitudinal, or behavioral characteristic that can take on different values
  8. 8. Variables • Can take on only specific values (e.g., whole numbers); no other values can exist between these numbers. Discrete • can take on a full range of values (e.g., numbers out to several decimal places); an infinite number of potential values exists. Continuous
  9. 9. Variables and Research • at least two levels that we either manipulate or observe to determine its effects Independent Variable • The outcome variable that we hypothesize to be related to, or caused by, changes Dependent Variable • systematically varies with the independent variable so that we cannot logically determine which variable is at work Confounding Variable
  10. 10. Levels of Measurement • variable used for observations that have categories, or names, as their values Nominal • variable used for observations that have rankings (i.e., 1st, 2nd, 3rd, . . .) as their values. Ordinal • variable used for observations that have numbers as their values; the distance (or interval) between pairs of consecutive numbers is assumed to be equal. Interval • a variable that meets the criteria for an interval variable but also has a meaningful zero point. Ratio