Stats - Chapter 1
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Political affiliation (republican, democrat)
-discrete -qualitative -nominal
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Season
-discrete -qualitative -nominal
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Sex (male, female)
-discrete -qualitative -nominal
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement A letter grade (A,B,C,D,F)
-discrete -qualitative -ordinal
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement A college student's SAT score
-discrete -quantitative -interval
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Ratings of satisfaction (1 to 7)
-discrete -quantitative -interval
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Rating of satisfaction (1 to 7)
-discrete -quantitative -interval
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Position standing in line
-discrete -quantitative -ordinal
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Ranking of favorite foods
-discrete -quantitative -ordinal
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement A letter grade
-discrete -quantitative -ordinal
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Ranking of favorite food
-discrete -quantitative -orinal
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Number of dreams recalled
-discrete -quantitative -ratio
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Number of errors
-discrete -quantitative -ratio
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Number of lever presses per minute
-discrete -quantitative -ratio
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Number of students in your class
-discrete -quantitative -ratio
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Number of errors
-discrete -quantitative -ratio
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Number of people in our class
-discrete -quantitative -ratio
3 common research methods
-experimental method -quasi experimental method -correlational method
Examples of variables
-gender -GPA -economic status
Nominal
-identity or classification -gender (1=female, 2=male), political affiliation (1=republican, 2=democrat), body type (1=slim, 2=average, 3=heavy)
What happens to the mean when you change an existing score?
-it will change -when you increase the value of an existing score the mean will increase -when you decrease the value of an existing score the mean will decrease
What is needed to satisfy experimental method?
-manipulation -randomization -comparison/control
What is mean reported for?
-normal distributions of data -only interval and ratio scale data
Ratio
-order, equal units, absolute zero -height in inches, weight of an infant, duration of drug abuse, scores on an exam (from 0% to 100%)
Ordinal
-rank or order and no equal units -Class rankings first through last, ranking of favorite food, letter grade (1=a,2=b,3=c,4=d,5=f)
Ratio scale
-same as interval scale but has true origin -zero means absence of what is being measures (income $0 means no income, weight, height, length)
What is median reported for?
-skewed distributions of data -ordinal scale data (not for nominal scale data)
What is modal distributions of data?
-unimodal distributions (one mode) -bimodal distribution (two modes) -multimodal distribution (more than two modes) -nonmodal distribution (no modes)
Rules for correlational method
-variables measured as they naturally occur -lack of random assignment -lacks control to determine cause-effect
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Sex (male, female)
-discrete -qualitative -nominal
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Type of distraction (auditory, visual)
-discrete -qualitative -nominal
Types of statistics
descriptive and inferential
How to find the interval width
divide the real range by the intervals needed
Population
entire set of individuals or items of interest. the group that scientists will generalize
A researcher tests whether the dosage level of some drug (low, high) causes significant differences in health. To do this, the researcher randomly assigns rat subjects to receive a low or high dosage of the drug and records health-related measures in both groups. The type of method described is
experimental
2 types of groups
experimental and control
Experimental group
exposed to manipulation
Inferential stats do what?
generalize to population
Interval scales of measurement A) have equidistant scales B) have a true zero C) both a and b
have equidistant scales
Benefits of experimental method
high level of control to isolate cause and effect
What is an operational definition?
how the DV will be measured
Examples of scales of measurement
identity, order, equal distance, absolute zero (complete absence of the variable)
What does randomization (random assignment) do?
renders groups equivalent
What is nominal scale data
represents something or someone; it is not a quantity
Exhaustive categories
response categories that cover the full range of possible responses
M means
sample mean
Data for samples are called?
sample statistics
What is most behavioral stats done on?
samples
x means
score or response
Levels
specific values of an independent variable
Experimental research
studies that seek clues to cause-effect relationships by manipulating one or more factors (independent variables) while controlling others (holding them constant)
How to find the real range?
subtract the least from the most data amount and add 1
Descriptive stats do what?
summarize sample results
Examples of interval scale
temperature, time
What does random assignment mean
that experimental units are assigned to treatments at random
Qualitative variables
variables that can be placed into distinct categories, according to some characteristic or attribute
Independent variable
variables that were manipulated (presumed cause)
Identify the dependent variable and independent (or quasi-independent) variable. A researcher tests whether smoking by parents influences children's attitudes toward smoking behavior.
IV smoking DV childrens attitudes toward smoking behavior
Identify the dependent variable and independent (or quasi-independent) variable. A student tests whether tutoring from a tutor improves performance on a standardized exam.
IV tutoring DV performance on a standardized exam.
Identify the dependent variable and independent (or quasi-independent) variable. A researcher tests whether the type of distraction during recall (auditory or visual) influences the number of words participants are able to recall from a list.
IV type of distraction during recall (auditory or visual) DV the number of words participants are able to recall from a list.
Identify the dependent variable and independent (or quasi-independent) variable. A psychologist tests whether employee satisfaction is different among employees working different shifts (day or night shifts).
IV working different shifts (day or night shifts). DV employee satisfaction
Nominal scale of measurement
Lowest of the four levels of measurement Categories that are not more or less, but are different from one another in some way Mutually exclusive and exhaustive categories Named categories Example: Gender 1 = Male 2 = Female
Statistics
Mathematical procedures used to summarize, analyze and interpret observations (5 senses)
Control group
Not exposed to manipulation
Data
Numbers assigned to observations according to rules, called scores or raw scores
Interval scale of measurement
Numerical distances between intervals Absence of a zero point Like scale scores 1 = Strongly disagree 2 = Disagree 3 = Neutral 4 = Agree 5 = Strongly agree
What is the gold standard scale of measurement?
Ratio scale
Research method
a set of systematic techniques used to acquire, modify and integrate knowledge concerning observable and measurable phenomena
Treatment
a specific condition that the experimental unit receives
Correlational stats
a statistical technique that can show whether and how strongly pairs of variables are related
What is an experiment?
a study in which we actually do something (a treatment) to people, animals, or objects (experiment unit) to observe the response
What is an independent variable (IV)?
a variable that is manipulated, the proposed cause
Discrete variable
a variable whose value is obtained by counting (whole #)
What is experimental method used for?
cause-effect analysis
What are the scales of measurement?
degree to which measured variables conform to the abstract number system
Sample
a representative subset of a population
Raw scores
data that have not yet been transformed or analyzed
What scale of measurement can be used for order?
ordinal, interval, ratio
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Body type (slim, average, heavy)
-discrete -qualitative -nominal
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Political affiliation (republican or democrat)
-discrete -qualitative -nominal
What is mode reported for?
-Modal distributions of data -nominal scale data
Interval scale
-Numerically equal distances on the scale represent equal distances on the underlying dimension -zero does not mean the absence of what is being measured
Interval
-Order and equal units, no true zero -Intelligence test scores, temperature, ratings of satisfaction (1=strongly disagree to 5=strongly agree)
Descriptive statistics
-Summarize, organize and make sense of a set of scores -procedures typically used to quantify measured behaviors -allows for clear presentation of data summary (tables, graphs, single values)
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Seasons (spring, summer, fall, winter)
-discrete -qualitative -nominal
Quasi-Experimental method includes what
-a non-manipulated IV -lack of random assignment to group and/or -lack of control group
What is correlational method used for?
-analyses for prediction -quantifies the strength and direction of a relationship between two or more variables (x and y)
Steps of research
-ask a question -set up a research study -measure behavior -evaluate findings
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Temperature (degrees fahrenheit)
-continuous -quantitative -interval
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Temperature
-continuous -quantitative -interval
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Duration of drug abuse (in years)
-continuous -quantitative -ratio
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Score (from 0% to 100%) on an exam
-continuous -quantitative -ratio
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement The size of a reward (in grams)
-continuous -quantitative -ratio
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Time (in seconds) to memorize a list
-continuous -quantitative -ratio
Continuous vs Discrete Qualitative vs Qualitative Scale of measurement Weight (in pounds) of an infant
-continuous -quantitative -ratio
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Duration of drug abuse
-continuous -quantitative -ratio
Continuous vs Discrete Qualitative vs Quantitative Scale of measurement Weight (in pounds) of an infant
-continuous -quantitative -ratio
Ways to classify variables
-continuous and discrete -quantitative and qualitative
Types of classification of variables
-continuous vs discrete -quantitative vs qualitative
Inferential statistics
-data typically drawn from a portion of the overall group of interest -allows researches to make inferences about parameters in a population based on a sample of data
Correlational methods
A research method that examines how variables are naturally related in the real world. The researcher makes no attempt to alter the variables or assign causation between them.
Quasi-experimental research
A research technique in which the two or more groups that are compared are selected based on predetermined characteristics, rather than random assignment and cannot manipulate the independent variable
Continuous variable
A variable (such as age, test score, or height) that can take on a wide or infinite number of values.
What are parameters?
Characteristic that describes a population
Identify the dependent variable and independent (or quasi-independent) variable. A professor tests whether students perform better on a multiple‐choice or fill‐in‐the‐blank test format.
DV students perform IV fill in the blank test format
Scale of measurement for ordinal question
Does a larger number indicate a greater value than a smaller number
Scale of measurement for ration question
Does dividing (or taking the ratio of) two numbers represent some meaningful value
Scale of measurement for difference question
Does subtracting 2 numbers represent some meaningful value
Identify the dependent variable and independent (or quasi-independent) variable. A health researcher tests whether the number of calories in a meal changes liking for that meal among a sample of adults.
IV number of calories DV liking for that meal
Ratio scale of measurement
Highest form of measurement and meets all of the rules of other forms of measurement; -mutually exclusive categories -exhaustive categories -ordered ranks -equally spaced intervals -a continuum of values
Identify the dependent variable and independent (or quasi-independent) variable. A social scientist tests whether attitudes toward morality differ based on political affiliation (Democrat or Republican).
IV political affiliation (Democrat or Republican) DV attitudes toward morality
Identify the dependent variable and independent (or quasi-independent) variable. A cultural researcher tests whether individuals from different cultures share or differ in the belief that dreams have meaning.
IV individuals from different cultures DV the belief that dreams have meaning.
What scale of measurement can be used for equal units?
Interval and ratio
An education counselor records the number of high school graduates enrolled in community colleges, four-year colleges, and universities. What scale of measurement is the type of college? A) nominal B) ordinal C) interval D) ratio
Nominal
Example of continuous classification
Olympic sprinters time to finish race, duration of drug abuse, score (0-100%) on an exam, temperature, age, weight
Ordinal scale of measurement
Order/ranking imposed on categories Numbers must preserve order 1 = Tallest 2 = Second tallest 3 = Third tallest
Researcher A measures academic preparedness as the percentage correct responses on an entrance exam; Researcher B measures preparedness as the current class rank of students. Which researcher measured academic preparedness as discrete data? A) Researcher A B) Researcher B C) both researchers D) no researchers
Researcher B
How to setup a research study
Select participants and create groups (2 groups drink grapefruit juice, one with and one without sugar)
Discrete classification
Separate and indivisible categories, whole numbers only
Examples of discrete classification
Socioeconomic class, gender, ranking of favorite foods, letter grade, body type (slim, average, heavy), ratings of satisfactions (1 to 5)
E(x-M)^2
Sum of the squared differences of scores
E(x-M)=0
Sum of thee differences of scores
Dependent Variable (DV)
The measured outcome (response) of a study
Dependent variable
Variables that were measured when IVs are manipulated (presumed effect)
Quantitative classification
Varies by amount, measured numerically and often collected by measuring or counting; continuous and discrete variables (ratings of satisfaction (1 to 5), height, weight)
Qualitative classification
Varies by form or class, often represented as a label and describes nonnumeric aspects of phenomena, only discrete variable, correspond to nominal scales, ordinal scale variable is typically qualitative but can also be quantitative
Continuum of values
a continuous series of elements or items that vary by such tiny differences that they do not seem to differ from each other. Example: a range of temperatures
Ogive
a graph that represents the cumulative frequencies for the classes in a frequency distribution
Variable
a numerical characteristic or condition that varies or has different values for different individuals (gender, GPA, etc)
Descriptive stats are procedures used to A) summarize a set of scores or observations B) organize a set of scores or observations C) make sense of a set of scores or observations D) all of the above
all of the above
Central tendency
average
_____________ are measured along a continuum at any place beyond the decimal point A) continuous data B) discrete data C) qualitative data D) open-ended data
continuous data
A researcher measures the body temperature (in degrees Fahrenheit) of participants immediately before and immediately following sleep. Temperature is on what scale of measurement? A) nominal B) ordinal C) interval D) ratio
interval
What scale of measurement can be used for differnce?
interval and ratio
How does randomization help experiments?
it helps minimize potential impact of irrelevant factors allowing us to attribute the observed outcome differences to the treatment variables
What happens to the mean if you add or take away a score?
it will change it unless the value equals the mean
What is important when constructing a frequency distribution?
make sure you could the number and dont just subtract because it will be wrong
Continuous classification
measured along a continuum, measured at any place beyond the decimal point
What is data?
measurements or observations
Nominal used for
naming, labeling, grouping, categorizing (dog-1, cat-2), cannot do math on these numbers
Scales of measurement
nominal, ordinal, interval, ratio
State the four scales of measurement in order from lease informative to most informative
nominal, ordinal, interval, ratio
Quantitative variables
numerical and can be ordered or ranked
Parameter
numerical descriptor of population, denoted by greek letters
Sample statistic
numerical descriptor of sample, denoted by latin letters (M, SD, etc)
Ordinal scale
numerically equal distances on the scale do not necessarily represent equal distances on the dimension underlying the scale (differences between 1 and 2 are not equally distant) (no arithmetic operations on the numbers can be performed)
A consultant ranks the five most needed areas of improvement for a local business. What scale of measurement are the rankings?
ordinal
Types of scales of measurement
ordinal, interval, ratio
Relative percent
percentage of scores that occurred in an interval
Each of the following is an example of quantitative data except A) weight in ounces B) income in dollars C) political affiliation D) age in years
political affiliation
Data for population are called?
population parameters
___________ data describe numeric aspects of phenomena; whereas ___________ data describe nonnumeric aspects of data
quantitative, qualitative
Types of research methods
quasi-experimental, correlational, experimental
Three key elements of control that allow researchers to draw cause-and-effect conclusions
randomization, manipulation, comparison/control
What scale of measurement can be used for absolute zeros?
ratio
What are scales of measurement used for?
to determine the type of statistical analyses possible
How does the scientific research process begin?
with a question or statement that can only be answered or addressed by making an observation
What is the sum of the differences of scores from their mean?
zero
