PSY 303 (RMS I) Final Exam

(Pilot)

What is Psychology?

• The study of behavior and mental processes

  • The same methods that are used for biology, chemistry, and physics can be applied to study behavior, thought, emotion, and physiological processes

What is Behavioral Science?

• Philosophers pondered human nature

• Speculative explanations of behavior changes to empiricism 

  • 1st Psychology Lab: Wilhelm Wundt

    • Established in 1879

What goals do psychologists have?

• Describing behavior: 

  • Focus is describing patterns of behavior, thought, or emotion

• Predicting behavior: 

  • Focus is on developing equations to predict behavior (when and why it may/ might occur)

• Explaining behavior: 

  • Focus is on developing theoretical explanations for patterns of behavior

What is basic research?

• Conducted to understand psychological processes without regard for whether or not the knowledge is immediately applicable

What is applied research?

Conducted to find solutions for problems rather than to enhance general knowledge about psychological processes

What is the scientific approach?

Systematic Empiricisim, Public Verification, Solvable Problems

What is empiricism?

Knowledge comes from our senses, i.e. observation

What is Systematic Empiricism?

Systematic observations to draw conclusions

What is public verification?

Findings must be replicated

What is a hypothesis?

• An educated prediction

• Precise: must describe a specific testable outcome in your study

  • Based on past research

What is “A Priori”

Before results predictions

What is “Post Hoc”?

After results prediction

What does falsification mean?

Theories must be falsifiable/ able to be disproven

What is a variable?

• Any factor that can change, be manipulated, or controlled in an experiment

• Note: Variable can be ANYTHING!

What does it mean to conceptually define a variable?

• Much like a definition that one would find in a dictionary

  • Ex: Depression - a persistent feeling of sadness and loss of interest/ it can also cause a variety of emotional and physical problems

What does it mean to operationally define a variable?

• Specifies precisely how a concept is measured

  • Ex: Cumulative scores…

What is natural setting in an experiment?

• Have no intrusions or interruption by the researcher (ex: observing choice of soft drinks at a restaurant from a distant table)

  • Know they are acting genuine because they don’t know they are being observed

What is contrived setting in an experiment?

• (Laboratory) settings are designed for observing behavior (ex: sign up for a study and get watched while eating)

  • May change behavior because they are being watched

What is disguised observation?

• Researcher conceals that behavior is benign recorded

  • Privacy & consent issues

What is Non-Disguised Observation?

• when people know they are being watched

  • Hawthorne Effect (reactivity)

How to Write Effective Questions?

• Use precise language

  • “What do you do after class?”

• Use basic words without jargon

  • “Have you used the ILL service?”

• Don’t make assumptions

  • “How many apps do you have on your phone?”

• Avoid double-barreled questions

  • “This service is interesting and useful.”

What is Social Desirability Response?

• Acknowledging that people may engage in behaviors that are NOT socially desirable but in an interview will not be honest about participating in said behaviors

What is Acquiescence?

Always agreeing

What is Nay-Saying?

Always saying no

What is Descriptive Research?

Describes behavior

What is Correlational Behavior?

Examines relationship between variables

What is Experimental Research?

Allows us to study causes of behavior

What is Quasi-Experimental Research?

• When the researcher wants to study the effect of naturally occurring variables 

  • In this situation they would not vary the independent variable by group

What is simple random assignment?

• Everyone has an equal chance of being assigned to any group/ condition

  • Ex: flip a coin, roll a die, etc.

  • Conditions are mostly equivalent

    • People with any attribute are equally likely to be in either group

What is matched random assignment?

• Ensures conditions will be similar along specific dimensions

  • Participants are matched into homogenous blocks

  • Participants in each block are assigned randomly to conditions

What is a within-subjects (repeated) design?

• Repeated measures

• Difference due to IV

• Participants experience all conditions

  • All levels of the IV

• No need for random assignment

  • Tested against your prior behavior

• Pros: 

  • More powerful

    • Power = ability to detect IV effects

  • Requires fewer participants

• Cons: 

  • Order effects

    • Doing multiple tests changes behavior

    • Examples: 

      • Carryover Effect: one condition impacts the other

      • Practice Effect: Learn from previous

      • Fatigue Effect: energy is depleted

      • Sensitization: Realize hypothesis

What is counterbalancing?

• Used to combat order effects

• Presenting levels of IV in different orders

What are confounds?

• A variable other than the IV that differs systematically between conditions

  • Invalidates experiment

    • Unclear whether difference are due to IV or confound

  • Must be eliminated at all costs

What is Internal Validity?

• Determines degree to which we can draw accurate conclusions about the effects if IV

  • Occurs when all confounds are eliminated

    • Can conclude that the observed differences were due to the IV

  • Achieved through experimental control

  • But some error is always present

What is external validity?

• Inverse relationship with internal validity

  • The more internally valid a study is (greater experimental control) the less likely it will be externally valid (generalizable to the “real world”)

  • Internal validity is more critical than external validity

What is a between-subjects (independent) design?

• Independent measures

• Individual differences

• Differences due to IV

• Participants experience one condition

• Typically requires random assignment

• At least 2 distinct groups (control and experimental)

What is the median?

• Scores are listed in order from smallest to largest

• The median is the midpoint, it equally divides the scores

• When to use it?

  • The median is used on ordinal, interval, or ratio data

  • The median isn’t changed by extreme scores (aka outliers), so it can be a good alternative to the mean

What is mode?

• The mode is the most frequently occurring score (aka which score(s) show(s) up the most)

• Can be used on any scale of measurement (nominal, ordinal, interval, or ratio)

What is a bar graphs?

Frequency distribution graph used when the score categories (X values) are measured on a nominal or an ordinal scale

what is a histogram?

Frequency distribution graph when the data is measured on an interval or ratio scale

What are polygons?

• Also used for interval or ratio scales

• A histogram, but with dots and lines

• For exact frequency tallies, your distribution will have jagged edges

• For relative frequencies (estimates of populations), your distribution will have smooth edges

What are positively & negatively skewed distributions?

• Skewed distributions pile up on one side, leaving a “tail” of a few extreme values on the other side

• Positively Skewed = tail goes to the right (towards positive numbers)

• Negatively Skewed = tail goes to the left (towards negative numbers)

• Hint: 

  • Mean > Median = positive

  • Mean < Median = negative

  • Mean = Median = normal

What is measurement error?

Variability in scores due to factors that distort the true score

What is True Score?

The score a participant would obtain if a measure were perfect and we could measure without error

What is reliability?

• Consistency/ dependability of the measuring technique

• Reliability has an inverse relationship with measurement error (the less error is present = more true scores present)

• If observed scores are close to true scores, the measure has high reliability

  • Ex: A watch that runs correctly but is always 30 minutes fast is very reliable despite low validity

What is correlation coefficient?

• A value which describes the relationship strength between two measures

  • Can range from -1.00 to +1.00

  • Correlation of 0.00 indicates no relationship

  • Sign indicates direction

What is interrater reliability?

Consistency among two or more researchers who observe and record participants behavior

What is test-retest reliability?

• Consistency of responses on a measure over time

  • Use the same measure twice

  • Examine the correlation

    • Correlation > 0.70 is desired

  • Measurement result should NOT change over time

What is inter-item reliability?

• Consistency between items on a scale (not entire measure)

• Tells us whether all of the items on a scale are measuring the same thing

• If not, measurement error increases and reliability decreases

  • Pro-Tip: Multiple items measuring the same thing are called scales

• Indices of Inter-Item Reliability: 

  • Item-total Correlation: The correlation between one item and the sum of all the other items on a scale

What is split-half reliability?

Divide the items on a scale into 2 sections and examine the correlation between the sections

What is Cronbach’s Alpha (a)?

• The average of all possible split-half reliabilities

  • Most frequently used

  • a > 0.70 is considered acceptable

What are some methods for increasing reliability?

• Standardize how measure is administered

• Clarify instructions and questions

• Train researchers/coders

• Minimize errors in coding data

What is validity

• How accurate is a measure at estimating what it is supposed to assess?

• Do differences in scores truly reflect differences in what we are trying to measure?

  • Ex: A watch that tells the right time has high validity, and broken watch will be valid twice a day

What is face validity?

• The extent to which a measure appears to measure what it’s supposed to measure

• Does NOT actually impact ‘true’ validity

What is construct validity?

• How well does measuring a hypothetical construct relate to other measures

  • TIP: A hypothetical construct is something that cannot be directly observed but is inferred based on observation or experience

What is convergent validity?

A measure correlates with the other measures that it should correlate with

What is discriminant validity?

A measure does not correlate with other measures that it should not correlate with

What is Fairness & Bias?

• Test bias occurs when a particular measure is not equally valid for everyone

  • The question is not whether various groups score different on the test

  • Test bias is present when the validity of a measure is lower for some groups than for others

What are inferential statistics?

• Are used to detect patterns, and variability influences how easily they are detected: 

  • Low variability = easier to see

  • High variability = more difficult

What is standard deviation?

• Measures the standard (average distance between a score and the mean

• Can only be used for interval and ratio scales

• Most commonly used

• Most important measure of variability

What is range?

• Total distance covered by the distribution, form highest to lowest value

• Describes the number of categories when we are using numbers or discrete groups

• Range = Max - Min

• However, range relies on two values (extremes), ignores all others

What is variance?

Is calculated using all scores from a distribution

What is probability sampling?

Can quantify the likelihood of being selected

• Know selection probability, accurately describes a population/ Rarely used in behavioral science

• Must be a representative sample

  • Simple Random

  • Systematic

    • Stratified Random

    • Cluster

What is non-probability sampling?

Can’t quantify the likelihood of being selected

• Types of non-probability sampling include…

  • Convenience

  • Quota

  • Snowball

Convenience sampling

• Easy to reach

• Most common type of sampling

Quota sampling

• Specific proportions of people with selected characteristics

Snowball sampling

• For hard to reach groups

• word of mouth process

• recruit people and they recruit people

What is Utilitarianism?

• Ethics judged according to consequences 

  • E.g., benefits should outweigh costs

  • Hedonism + Consequentialism = Utilitarianism

  • Maximizes happiness

  • Minimizes unhappiness

  • Outcome is what matters

• Benefits of Utilitarianism: 

  • Improved techniques

  • Practical outcomes

  • Benefits for researchers

  • Benefits for participants

• Costs of Utilitarianism: 

  • Time and effort

  • Participants’ welfare

  • Money

  • Deception; creating distrust

What is deontology?

• Judged according to universal moral code

  • E.g., deceit is always wrong

  • Intentions matter

  • Ex: poison your partner

What is Ethical Skepticism?

• Concrete moral codes can’t be made

  • E.g., decisions are based on your conscience

What is probability?

• Likelihood of all possible outcomes

• “probability “ = p

• Can we quantify this? A fraction, decimal, or percentage: 

  • P = ½ = 0.50 = 50%

• Goes from 0% to 100%, or “0” to “1”

• Probability of A = # of outcomes classified as A/ total # of possible outcomes

• Low probability values = special/rare! Not common or likely to happen = EFFECT

• High probability values = Pretty common/likely to happen = NO EFFECT

Probability & Sampling

• Quantifies relationship between sample & population

• When something occurs in a sample, how likely is it that it represents the population?

• Probability calculation sometimes requires independent random sampling (Convenience sampling for our project)

  • Equal chance

  • Replacement

Probability & Frequency Distribution

• Graphs display a population of scores

• Proportion of graph = proportion of population

• Probability can be defined by a proportion of the graph

Probability & Normal Distribution

• Can determine likelihood that a score falls in shaded area

• Line location specified by z-score

• Tail = smaller section

• Body = larger section

What is Z- Score?

• Z = M - miu/sigma(M) -> [standard error]

• Describes one sample’s location in the sampling distribution

• Focused on a singular score

  • But usually in our field, focused on more than that

  • We can calculate z scores for entire samples

What is Sampling Distribution?

Distributions of statistics that consists of all of the possible samples of a specific size from a population

• Most sample means will pile up around the population mean

• Should form a normal distribution if…

  • The population is normally distributed

  • Number of scores in each sample is 30+

• Larger samples are more representative than smaller samples

What is Distribution of Sample Means?

• Collection of sample means for ALL POSSIBLE random samples for a size (n) that could be obtained from a population

What is Hypothesis Testing?

• We usually can’t measure everyone in a population

  • We use sample data to evaluate a hypothesis about a population

  • Take a sample, expose it to your I.V., make an inference to the population

    • Inferential Statistics

• Factors that Influence a Hypothesis Test: 

  • Variability of scores

  • Number of scores in the sample

What are the steps for hypothesis testing?

• Step 1. State a Hypothesis: 

  • State a hypothesis actually means that you will state 2 hypotheses

    • H0 = Null (no difference) -> Treatment (IV) has no effect on the outcome (DV)

    • H1 = Alternate (Difference) -> Treatment (IV) does have an effect on the outcome (DV)

• Treatment = IV = Manipulation = Experimental Group

• Step 2. Set Decision Criteria: 

  • Decision Criteria (a = alpha value)

  • Less than 5% probability (p) of error is okay with social science

    • 5% = 5/100, 0r 0.05

    • Alpha a = 0.05

    • Probability of error (p) should be < 0.05

  • Also sets the critical regions

  • If the results of a sample who has received the treatment falls within the critical region it is very unlikely

• Step 3. Collect Data, Compute Stats: 

  • Collect data is self-explanatory

• Step 4. Make Decision: 

  • What are the choices?: 

    • 1. Reject Null Hypothesis

    • 2. Fail to reject Null Hypothesis

What does it mean to reject the null hypothesis?

• Saying there is a difference between groups

  • IV had a significant influence on the results

What does it mean to fail to reject the null hypothesis?

• Saying there is no difference between groups

  • IV did not have a significant influence on the results

What is Type I Error?

• False Positive - Rejecting a true Null Hypothesis

What is Type II Error

False Negative - Failing to reject a false Null Hypothesis

What is nominal scale of measurement?

• Numbers are assigned as labels

• Least amount of information

What is ordinal scale of measurement?

• Rank ordering

  • More than just a label

  • Doesn’t tell us distance

What is interval scale of measurement?

• Equal differences between numbers reflect equal differences

• NO TRUE ZERO

  • Zero is just another point in the dataset, doesn’t represent the absence of something

What is ratio scale of measurement

• Contains a TRUE ZERO

  • Doesn’t matter is zero “can” happen, only what it’s defined by

• Greatest amount of information

• Use when possible

• Least informative

What is a normal distribution and where is the mean, median, and mode?

What is a positive skew and where is the mean, median, and mode?

What is a negative skew and where is the mean, median, and mode

A perfectly reliable measure has what?

Has no measurement error

A sunset of the population that shares a particular characteristic is called what?

Stratum

A design with high what will detect whatever actual effects are present?

Power

___ is to some as ___ is to all?

Sample, population

What is the best measure of central tendency for nominal data?

Mode

What is the typical preferred measure for central tendency when it comes to outliers?

Median

What occurs when a particular measure is not EQUALLY VALID for everyone?

Test bias

what is s²

Variance

what is s?

standard deviation

When X values (raw scores) are transformed into Z-scores the resulting distribution of Z-
scores always has a standard deviation of ___ and a mean of ___.

1 & 0 respectively