PSYCH 311 1st Edition Exam 1 Study Guide Lectures 1 5 Lecture 1 August 22 Core Components Through science wisdom and helping one is able to understand and appreciate humanity Science and wisdom combined create a paradigm understanding Wisdom and helping combined enable self development Helping and science combined allow us to apply our knowledge Introduction to the Scientific Method The scientific method allows us to approach and answer questions systematically Observe behavior or phenomena Form a hypothesis with variables Generate testable prediction Evaluate prediction using systematic empiricism Do the observations support refute refine the hypothesis Share and replicate findings Lecture 2 August 27 Introduction to Statistics Statistics is the part of the scientific method that allows us to answer research questions and allows us to be objective while interpreting the data Population and Sample Samples are a representative subset of the population Sampling errors are caused by the discrepancy between samples and populations Types of Statistics The data or datum and the research question in play determines which methods to use Descriptive Statistics Inferential Statistics Discrete Categorical Variables Continuous Variables Defining and Measuring Variables Variables are situations in which characteristics conditions change this is represented by a numerical value and the specific value for a given person is the score Depending on the situation different variables are used Participant Variables Environmental Variables Independent Variables Dependent Variables Constructs and Operational Definitions Constructs must be quantifiable although they cannot be directly observed but are useful for describing or explaining behavior never use a construct to define a construct While operational definitions identify procedures describe sets of observations and define constructs in terms of resulting measurements Lecture 3 August 29 Scales of Measurement There are four scales of measurement nominal ordinal interval and ratio The data used determines which scale of measurement is used Discrete Variables are used to answer how many Nominal Ordinal while continuous variables answer how much Ordinal Interval Ratio Symbols Stats Size Mean Variance Standard Deviation SD Population Sample n M s s Descriptive statistics allows you to get a general idea of the whole set of data using graphs measures of central tendency or measures of variability Frequency tables allow you to view the frequency of a value using f N Lecture 4 September 3 What is the difference between a histogram polygon and bar graph Histograms are a type of bar graph that represents the frequency of scores within a category The width of bars must touch each other indicating interval or ratio scale of measurement Polygons are a type of line graph used for interval or ratio scales of measurement It is made up of connected dots centered above each corresponding score at the specific number of frequency Bar graphs are used to represent frequency scores for nominal or ordinal scales of measurement The bar heights corresponds to the frequency of that category Although the bars do not touch representing that it is a discrete category What are the different graphs for population distributions What do their shapes indicate Relative frequency distributions and smooth curves allow us to more accurately represent large populations Relative frequencies are used for nominal and ordinal data it is a bar graph with no numbers While smooth curves are line graphs used to indicate change from one category to another You can have a normal distribution bel curve a negatively skewed distribution or a positively skewed distribution In addition there can be unimodal or multimodal distributions depending on how many peeks there are or a symmetrical distribution How can the different measures of central tendency help explain our data Using the mode median or mean one is able to best represent the entire data set Each measure gives a different perspective on the population or sample Sample X X individual scores Sigma or sum of scores number scores Population is X X deviation score Lecture 5 September 5 How do you choose which measure of central tendency to use Once you graph the scores if you notice the scores are extreme skewed or open ended distributions or ordinal scale use the median If you are using a nominal scale or discrete variables or describing the shape of the distribution use the mode The mean is the most commonly used central tendency though it includes every score in the data set and is related to the variance and standard deviation If the distribution is symmetrical and normal the mean median and mode all equal each other If the distribution is symmetrical but not normal then the mean and median are equal which also equal two modes If the distribution is positively skewed the mean is always the highest value and the mode is the lowest Although if the distribution is negatively skewed the mode always has the highest value and the mean has the lowest Variability Rule The larger the value of variability the greater the spread of the scores We quantify variability by calculating the variance and standard deviation and population s and s sample X how far an individual score falls from mean X N on average how far individual scores fall from mean above and below s and s use df degrees of freedom n 1 as denominator allows us to correct sample bias