KIN 200 Unit 1
the average height of all women aged 20 to older
what is the parameter? A researcher wants to estimate the average height of women aged 20 years or older. From a simple random sample of 45 women, the researcher obtains a sample mean height of 63.9 inches.
the proportion of adults 18 or older who read a book in the previous year
what is the parameter? An education official wants to estimate the proportion of adults aged 18 or older who had read at least one book during the previous year. A random sample of 1006 adults aged 18 or older is obtained, and 835 of those adults had read at least one book during the previous year.
the average height of 63.9 inches from the sample of 45 women
what is the statistic? A researcher wants to estimate the average height of women aged 20 years or older. From a simple random sample of 45 women, the researcher obtains a sample mean height of 63.9 inches.
The statistic is 83% of people who read a book
what is the statistic? An education official wants to estimate the proportion of adults aged 18 or older who had read at least one book during the previous year. A random sample of 1006 adults aged 18 or older is obtained, and 835 of those adults had read at least one book during the previous year.
correlation
will not be an answer on the test f
The length of time in the internship
"Attitudes of physical therapy students toward physical therapy assistants before and after full-time clinical internships." -what is the independent variable that influences the attitudes of PT students?
the attitudes of PT students
"Attitudes of physical therapy students toward physical therapy assistants before and after full-time clinical internships." -what is the dependent variable being measured?
explosive performance
"The effect of static stretching on explosive performance." -what is the dependent variable being measured?
static stretching
"The effect of static stretching on explosive performance." -what is the independent variable that influences explosive performance?
number of ankle sprains
"The role of shoe design in ankle sprain rates among collegiate basketball players." -what is the dependent variable being measured?
shoe design
"The role of shoe design in ankle sprain rates among collegiate basketball players." -what is the independent variable that influences the number of ankle sprains?
Avis Effect
(Participant expectancy effect) - when subjects in a study discover the purpose of the study they could react by changing their behavior in some way, or "trying harder."
threats to internal validity
(a) Hawthorne effect (b) Experimental bias (c) Regression toward the mean (d) Avis Effect
Experiment (clinical trial)
-A carefully designed study that seeks to determine, under controlled conditions, the effectiveness of a treatment. -One or more variable is systematically manipulated to see their effect (alone or in combination) on an outcome variable. -Statements can be made about cause & effect.
Measures of Central Tendency
-mean, median, mode
temporal precedence
-the cause precedes the effect -one of three criteria for establishing a causal claim, stating that the proposed causal variable comes first in time, before the proposed outcome variable
Parameters
-values that represent a characteristic of a population such as: -the population mean -standard deviation -a percentage (%)
Parameters
-when we measure every member of a population, we can calculate values called _____________
The scientific method of problem solving
1. State the problem (the purpose of the study) 2. Form a hypothesis 3. Test the hypothesis -Design the study -Collect data -Analyze the data 4. Draw conclusions
variable
A factor that can change in an experiment.
Control variable
A held constant, or controlled, at one level throughout an experiment. For example, caloric intake would be controlled in a diet study; gender would be controlled in a strength study.
Sample
A parameter is a characteristic of a population. A statistic is a characteristic of a _________.
continuous variable
A quantitative variable that can be measured at an infinite number of levels depending on the accuracy of the measuring instrument.
sample
A relatively small proportion of people who are chosen in a survey so as to be representative of the whole.
independent
A research study typically looks at the effect of one or more ______________________ variables on a dependent variable. For example, "The effects of various caffeine doses (IV) on exam performance (DV)"
stratified sample
A sample chosen from a population that has been subdivided based upon predetermined characteristics such as gender, race, and socio-economic status.
stratified sample
A sample chosen from a population that has been subdivided based upon variables that are deemed to be important to the research question.
random sample
A sample drawn in such a way that all members of the population have an equal chance of being selected.
biased sample
A sample drawn in such a way that some members of the population are more likely to be chosen than others.
systematic sample
A sample obtained using a pre-determined system (not random). For example, choosing every 10th subject from the population.
convenience sample
A sample that is not randomly chosen and is typically used because of the availability of the subjects. Examples include using the students in a class as subjects, asking for volunteers, or using other methods of recruitment. There are no other criteria to the sampling method except that people be available and willing to participate. This is a biased sample.
representative sample
A sample that reflects the characteristics of the population from which it is drawn Randomly selected sample of subjects from a larger population of subjects
continuous variable
A variable (such as age, test score, or height) that can take on a wide or infinite number of values. A quantitative variable that has an infinite number of possible values that are not countable
Continuous
A variable is "_________________" if it can be measured on a continuum, such as a number line.
Discrete
A variable is "__________________" if its values, or "levels" have no values in between them.
Control variable
A variable that is held constant, or controlled, throughout an experiment. Exercise, food intake, gender, amount of sleep would be controlled in a diet study.
control variable
A variable that is kept constant during a controlled experiment.
Independent variable
A variable that you identify as having a potential influence on your dependent variable. -A treatment -A demographic factor like age or gender.
Independent variable
A variable that you identify as having a potential influence on your outcome measure. This might be a variable that you control, like a treatment. It also might represent a demographic factor like age or gender
Quantitative variable
A variable whose levels are described numerically (and the numbers are treated as numbers, not labels)
Qualitative variable
A variable whose levels are described with words or phrases (labels).
Discrete variables
A variable, either qualitative or quantitative, with a finite number of values that cannot be subdivided meaningfully.
Avis effect
In a weight loss study, the subjects in the control group might act like they are on a diet if they discover the purpose of the study The "placebo effect" is linked to this effect
Establishing Cause and Effect
Retrospective, prospective, and correlational studies do not allow us to draw conclusions about cause & effect. "Cause & effect" refers to an independent variable causing a change in the dependent variable.
Interval
Shoe size what scale of measurement would you use for this variable?
qualitative
Size (S, M, L, XL) is _______________
quantitative
Size in inches is ____________________
Examples of Tenacity
Some examples: Superstition Old wives' tales Astrology
Qualitative variables that are labeled with numbers
Some variables can be labeled with numbers but are qualitative because the numbers are used as labels. -Driver's license numbers -Jersey numbers on athletes -Serial numbers -Email addresses
variable
Something that can have more than one value.
Variable
Something that can take on more than one value Something that will be measured The various treatments
Representative
Statistics can be used to estimate parameters. The accuracy of our estimate depends on how ______________ our sample is of the population.
evidence
Statistics in numerical and/or graphical form are often used to provide supporting ______________ for an argument
mean
Statistics with interval level variables We can calculate an average (_________________). The average high temperature in Las Vegas during the month of August is 103 degrees.
median
Statistics with ordinal level variables We can find a middle point (_____________) because the levels of the variable can be rank ordered.
tenacity
Store batteries in a refrigerator to improve their performance which unscientific method of problem solving is this?
Hawthorne effect
Subjects in a study will react differently when they believe they are being studied/observed Some researchers believe this effect is simply a version of the placebo effect *threat to internal validity
Dependent variable
The outcome measure; the variable that is measured in a research study. It is affected by, or "dependent" on, the actions of other variables such as the independent variable(s).
Data collection process
The problem: the researcher is influencing the results. The solution: Remove the researcher from the _____________ ________________ ________________. Run a double blind study.
Population
all members of a specified group
Statistics
are values that represents a characteristic of a sample such as the sample mean, standard deviation, or a percentage %.
ordinal level of measurement
classifies data into categories that can be ranked; however, precise differences between the ranks do not exist a measurement of a variable in which the numbers indicating a variable's values specify only the order of the cases, permitting greater than and less than distinctions
unsystematic variability
in an experiment, when levels of a variable fluctuate independently of experimental group membership, contributing to variability within groups
nominal
sex/ gender what scale of measurement would you use for this variable?
variables
scales used to measure ______________ -nominal -ordinal -interval -ratio
ordinal
- Examples of ___________ data are often found in questionnaires: for example, the survey question "Is your general health poor, reasonable, good, or excellent?"
quantitative variables
- temperature - % body fat - age - time
Descriptive Statistics
- used in virtually every form of data analysis - they provide simple summaries about the person, thing, or sample being measured - they can be expressed as percentages, averages, ranges (variability), pictures and graphs
Prospective study
-A group of healthy subjects is enrolled and followed over time to determine the frequency with which a specific outcome develops. The sample may be grouped according to the presence or absence of a stimulus variable such as smoking history. -Does NOT allow us to draw conclusions about cause & effect. Example: A group of smokers and a group of non-smokers were observed across time with the intent of comparing the incidence of lung disease. These results suggest that smoking and lung disease are related. However, they do not prove that smoking causes lung disease.
ratio
-Age.* -Weight. -Height. -Sales Figures. -Ruler measurements. -Income earned in a week. -Years of education. -Number of children. what scale of measurement would you use for these variables?
Validity
-An instrument is "valid" if it measures what it is intended to measure. -Valid measurement instruments are essential to a successful research project. -An instrument must be "reliable" to be valid.
Using experimental groups that are not alike
-Care needs to be taken when assigning subjects to treatment and control groups -a cause of selection bias
Experiment example
-College students were randomly assigned to three experimental groups to determine the effect of caffeine on exam performance. -Assuming that both the treatment and control groups were equally prepared for the exam, there is evidence that 330 mg of caffeine is detrimental to performance on an exam.
Retrospective study
-Data is examined from selected cases and controls to determine differences, if any, in the exposure to a suspected factor. -Subjects are not "treated" and variables are not controlled, then cause & effect may not be inferred. -Does NOT allow us to draw conclusions about cause & effect. Example: Incidences of premature births were counted among mothers who smoked (case group) and mothers who didn't smoke (control group).
Measurement scales
-Every variable is measured at a specific "level" or "scale" of measurement. -The level of measurement determines the type of statistics we can use with the variable. There are four levels of measurement: 1. Nominal (the lowest and simplest level) 2. Ordinal 3. Interval 4. Ratio (the highest and most complex level)
ordinal
-High school class ranking: 1st, 9th, 87th... -Socioeconomic status: poor, middle class, rich. -The Likert Scale: strongly disagree, disagree, neutral, agree, strongly agree. -Level of Agreement: yes, maybe, no. -Time of Day: dawn, morning, noon, afternoon, evening, night. -Political Orientation: left, center, right.
Misinterpreting Statistics
-Statistics give us a "snapshot" of a situation -The "snapshot" can be used to support various agendas depending on the context in which it is used
Ratio level of measurement
-Ratio level variables possess all of the characteristics of interval level variables with the added characteristic of a measurement baseline. -This baseline represents a zero point on the measurement scale, or an absolute absence in quantity of the variable being measured. Examples, measured quantitatively, include: -height -weight -distance
Types of Research Studies
-Retrospective study (case-control study) (cross-sectional study) -Prospective study (cohort study) (longitudinal study) -Correlational study -Experiment (clinical trial)
Syllogism
-Some people can jump high -Basketball players are people -Therefore, some basketball players can jump high example of a:
Four unscientific methods of problem solving
-Tenacity -Intuition -Authority -Rationalism These "methods" may be successful at times, but they often have little or no factual support because they cannot be replicated.
External validity
-The degree to which the experimental results can be generalized to the target population. -The highest degree of external validity exists when all responses from subjects in the sample can be seen in the population. -For example, an average loss of 10 pounds in the sample would be mirrored by an average loss of 10 pounds in the population.
Unsystematic Variability
-The failure of a people in a sample to elicit the same response. This "variability" is due to factors we can't control. Examples: -Everyone does not score the same on a test. -Everyone does not have the same heart rate.
Unsystematic Variability
-The failure of a person to elicit the same response continually. This "variability" is due to random factors we can't control. Example: -You attempt to hit a target with a 2.7 gram ball. -You hit the target 4 out of 10 times. -Your errors around the target are "random error."
Ordinal level of measurement
-These are discrete variables (finite numbers: 1, 2, 3) -Unlike variables at the nominal level, variables at the ordinal level of measurement can be rank-ordered meaningfully. -We can count the number of times each value occurs and create percentages. -We can find a middle point (median) because the levels of the variable can be rank ordered. -We cannot calculate averages because the variables are either qualitative or the distance between the levels of a quantitative variable are not equal.
correlational study
-Two variables are examined to see if a mathematical relationship exists between them. -Does NOT allow us to draw conclusions about cause & effect.
Nominal Scale
-Variables at this measurement level are categorical, qualitative, and discrete in nature. -Although numbers may be used to represent the various values of the variables, the numbers are treated as labels. -We can count the number of times each value occurs. -can use "the mode" to measure central to measure central tendency -we can calculate the % of occurrences -we cannot calculate averages because the variables are qualitative, not quantitative
Statistics with ratio level variables
-We can count the number of times each value occurs. -We can find a middle point (median) because the levels of the variable can be rank ordered. -We can add and subtract values. -We can calculate an average (mean). -We can multiply and divide values. ex: 12 inches is twice as long as 6 inches (6 x 2 = 12). 100 pounds is half as much as 200 pounds (200/2 = 100).
Sampling
-We need to be sure our data represents the population of interest if we wish to make accurate and meaningful statements about our results. -We need to collect our data from a representative sample to get meaningful results.
Variability or "Error" in Measurement
-When we measure something or someone, we don't always get an accurate measurement. -The difference between a true value and the measured value is called "error." -"Error" does not always mean "mistake;" it simply means there is variability in measurements.
Volunteer bias
-a shortcoming of findings derived from a sample of volunteers instead of a representative sample; the volunteers may differ from those who did not volunteer -research has shown that volunteers do not have the same characteristics as the general population -a cause of selection bias
Sample
-a subset of a population -A relatively small proportion of people who are chosen in a survey so as to be representative of the whole -drawn from a population
Examples of variables
-blood type -weight -blood pressure -blood glucose -temperature -light -time -availability of nutrients -amount of drug administered -type of drug administered
Covariation of the cause and the effect
-effect occurs only in the presence of cause -when the cause is present, the effect occurs; when the cause is not present, the effect does not occur If X (the cause) happens, then Y (the effect) happens or... If X (the cause) does not happen, then Y (the effect) does not happen
Types of Variables
-independent -dependent -quantitative -qualitative -continuous -discrete
Parameter
A __________ is a characteristic of a population. A statistic is a characteristic of a sample.
interval scale
A ____________ _____________ has measurements where the difference between values is meaningful. In other words, the differences between points on the scale are measurable and exactly equal. For example, the difference between a 110 degrees F and 100 degrees F is the same difference as between 70 degrees F and 80 degrees F
Hawthorne effect
A change in a subject's behavior caused simply by the awareness of being studied
Hawthorne Effect
A change in a subject's behavior caused simply by the awareness of being studied, treated and tested Performance tends to improve
examples of quantitative variables
A country's population, a person's shoe size, or a car's speed
Syllogism
A deductive scheme of a formal argument consisting of a major and a minor premise and a conclusion. For example: -All men are mortal (major premise) -The emperor is a man (minor premise) -Therefore the emperor is mortal (conclusion)
controlled
Amount of weights, time would be ____________________ in a strength study.
Tenacity
An unscientific method of problem solving in which people cling to certain beliefs regardless of the lack of supporting evidence. Some examples: -Superstition -Old wives' tales -Astrology
Rationalistic method
An unscientific method of problem solving in which we derive knowledge through reasoning.
Intuition
An unscientific method of problem solving where a person has the ability to sense or know something without reasoning. It is thought to combine knowledge and awareness.
tenacity
Anything regarding predicting the sex of your unborn baby which unscientific method of problem solving is this?
extraneous variables
Assume we were studying the effect of caffeine (IV) on exam performance (DV) what kind of variables are the following? -amount of sleep -amount of studying -efficiency of studying
Experiment
Assuming that both the treatment and control groups were treated equally, except for the smoking, there is strong evidence that smoking causes lung disease.
correlational study examples
BP and body weight are positively related in adults. Cholesterol level and incidence of heart disease are positively related. Ice cream sales and crime rate are positively related. Socioeconomic status and the amount of fat in your diet are negatively related
Appeal to Authority
Belief that something is true because someone in an authoritative position claims it is true. Authorities: -Our parents -Our teachers -Clergy -The media
tenacity
Black cats are bad luck Don't open an umbrella inside which unscientific method of problem solving is this?
nominal
Brand of shoes: Adidas Nike Reebok Keds Converse Traks New Balance Stuart Weitzman what scale of measurement would you use for this variable?
the media
Celebrities and people in authoritative positions are used in _____________________ to influence us.
tenacity
Chewing gum takes 7 years to digest which unscientific method of problem solving is this?
nominal
Colors what scale of measurement would you use for this variable?
discrete variable
Consists of separate, indivisible categories. No values can exist between two neighboring categories.
Discrete
Continuous or discrete? Brand of car (Ford, Chevy, Plymouth, etc.)
discrete
Continuous or discrete? Class enrollment (number of people)
Discrete
Continuous or discrete? Eye color (brown, blue, green, red, etc.)
Discrete
Continuous or discrete? Heart rate (beats per minute)
Discrete
Continuous or discrete? Plastic straws (number of...)
Discrete
Continuous or discrete? Shoe size (measured in ½ sizes)
continuous
Continuous or discrete? Temperature in degrees
Discrete
Continuous or discrete? Type of dog (big, small, cute, ugly, etc)
Discrete
Continuous or discrete? Your opinion (agree, disagree)
continuous
Continuous or discrete? Distance in inches, feet, yards, miles, etc.
continuous
Continuous or discrete? Height in centimeters or inches
continuous
Continuous or discrete? Speed in miles per hour
continuous
Continuous or discrete? Time in hours, minutes, sec.
continuous
Continuous or discrete? Weight in pounds
inferential statistics
Descriptive statistics describes data (for example, a chart or graph) and ____________ _______________ allows you to make predictions ("inferences") from that data. With ________ ________________, you take data from samples and make generalizations about a population.
qualitative
Distance (near, far) is ________________________
quantitative
Distance in miles is __________________________
ordinal
Education experience Advanced degree College graduate Some college High School graduate Some high school Jr. High school U.N.R. graduate Elementary school what scale of measurement would you use for this variable?
Anecdotal evidence
Evidence based on personal accounts of incidents (biased) An informal observation that has not been systematically tested
Operational definitions
Example: The variable "body temperature" will be measured using an oral thermometer.
nominal
Examples: -Gender: Male, Female, Other. -Hair Color: Brown, Black, Blonde, Red, Other. -Type of living accommodation: House, Apartment, Trailer, Other. -Genotype: Bb, bb, BB, bB. -Religious preference: -Buddhist, Mormon, Muslim, Jewish, Christian, Other. what scale of measurement would you use for these variables?
Interval
Examples: Celsius Temperature. Fahrenheit Temperature. IQ (intelligence scale). SAT scores. Time on a clock with hands. what scale of measurement would you use for these variable?
Examples of qualitative variables
Examples: - color (red, white, blue) - sex (female, male) - size (small, medium, large) - political party (Democrat, Republican, D.S.)
continuous
Height discrete of continuous variable?
quantitative and continuous
Height is a _________________ and ______________________ variable
represents
How to reduce selection bias (sample does not represent the population): Ensure that the sample _____________ the population
Random assignment
How to reduce selection bias (sample does not represent the population): Use ____________ _______________ of participants to the different groups that you are comparing
stratified sample
How to reduce selection bias (sample does not represent the population): Use a _______________ ________________________ to help ensure that important characteristics in the population are included in the sample
Continuous
Identify the following as "discrete" or "continuous" variable The amount of time that randomly selected drivers spend texting while driving over the last 7 days
Continuous
Identify the following as "discrete" or "continuous" variable The exact foot lengths (cm) of a random sample of statistics students
discrete
Identify the following as "discrete" or "continuous" variable The number of A&P textbooks sold by the bookstore this semester
Discrete
Identify the following as "discrete" or "continuous" variable The number of people surveyed in the next National Health and Nutrition survey
inferential statistics
Inferential statistics use a random sample of data taken from a population to describe and make inferences about the population. Inferential statistics are valuable when examination of each member of an entire population is not convenient or possible.
The Rationalistic Method
Knowledge is derived through reasoning. Syllogisms are often used.
Drawing a stratified sample
N= sample size 1. Assume we want to choose a stratified sample from a population of 200 colored marbles. 2. The population of 200 marbles consists of: 12 blue 12 yellow 10 green 9 cat eyes 8 black 4 red N = 200 3. How would I draw a "stratified" sample of 50 (n = 50) from the 200 marbles? 4. Determine the proportion represented by each color
ordinal
Opinion polls often ask for your "amount of agreement." For example, indicate your amount of agreement with the following statement: "A college education should be free of charge." Strongly agree Agree Disagree Strongly disagree what scale of measurement would you use for this variable?
double blind study
Protecting against Experimenter bias: The problem: the researcher is influencing the results. The solution: Remove the researcher from the data collection process. Run a ____________ _________________ _______________
blind
Protecting against the Avis effect The problem: the subjects in the control group are over-reacting The solution: Don't let them know! Run a "____________" study - don't let the subjects know that there might be treatment and control groups Make them all think they are being treated
control group
Protecting against the Hawthorne effect: The problem: the subjects being treated are aware that they are being observed. The solution: Include a ____________ ________________ that is observed, but not treated. The _________________ __________________ control group thinks they are being treated, so the difference between the groups should be due to the treatment.
Interval scale
Temperature The distance between degree markings is consistent from top to bottom. what scale of measurement would you use for this variable?
Reliability
The ability of an instrument to produce the same results under the same conditions. An instrument must be "reliable" to be valid.
interval scale
The average high temperature in Las Vegas during the month of August is 103 degrees.
Parameters
The average lifespan of females in the USA = 79.1 years. The average % body fat of males between 18 and 25 years of age = 15%. Average IQ = 100.
Qualitative
The color of pills quantitative or qualitative?
Internal validity
The degree to which changing the level of the independent variable causes a change in the dependent variable. In an experiment, the highest degree of internal validity exists when all changes in the dependent variable can be attributed to the effect(s) of the independent variable(s).
ecological validity
The extent to which a study is realistic or representative of real life. Can we generalize from individuals who have experienced treatments (i.e., took part in the experiment) to people in the real world who have not experienced the same treatments (i.e., people who were not part of the experiment)? *threat to external validity
Unsystematic Variability
The failure of identically treated subjects to elicit the same response. Example: -We put 10 people, who all need to lose 10 pounds, on a 4-month diet and exercise program. -At the end of the 4-month period, the subjects did not all lose the same amount of weight.
Continuous and ratio level
The variable is "brain volume (cm3)" what level of measurement would you use for this variable?
Continuous and ratio level
The variable is "heights of randomly selected freshmen" in inches. what level of measurement would you use for this variable?
Discrete and ratio level
The variable is "number of motor vehicle fatalities." what level of measurement would you use for this variable?
Discrete and nominal level
The variable is "types of shrubbery" sold at Star Nursery what level of measurement would you use for this variable?
Continuous and ratio level
The variable is "upper arm circumference" in mm. what level of measurement would you use for this variable?
Dependent variable
The variable that is measured in a research study. -It is affected by, or "dependent" on, the actions of other variables such as the independent variable(s).
Quantitative
The weight of aspirin tablets quantitative or qualitative?
Threats to external validity
Threats to external validity are any factors within a study that reduce the generalizability of the results. Two examples are: (a) Selection bias (b) Ecological validity
cause-effect relationship
Three criteria need to be met for us to establish a _____________________ ______________________________ -Temporal precedence -Covariation of the cause & the effect -No plausible alternate explanations exist
No plausible alternate explanations
Treatment ------> Outcome
Extraneous variables
Undesirable variables that influence the outcome of the study (unwanted, unaccounted) Assume we were studying the effect of caffeine (IV) on exam performance (DV), extraneous variables would include amount of sleep, amount of studying, etc.
Extraneous variable
Undesirable variables that influence the relationship between the variables that an experimenter is examining. These variables are undesirable because they add error to an experiment. A major goal in research design is to decrease or control the influence of extraneous variables as much as possible.
Systematic Variability
Variability, or error in a measurement, that is caused by something we can account for. Example: -A sample of patients with high cholesterol are prescribed a cholesterol-lowering medication. -Their LDL decreases from an average of 220 to an average of 160 over the course of several months. -The variability in measurements is due primarily to the medication (something we can account for).
Interval level of measurement
Variables at this level may be quantitative or qualitative, discrete or continuous. They possess the characteristics of ordinal level variables with the added characteristic of equal intervals between levels We can count the number of times each value occurs. We can find a middle point (median) because the levels of the variable can be rank ordered. We can add and subtract values. We can calculate an average (mean). We cannot multiply or divide the values of an interval level variable because it has an arbitrary zero point - interval level measurement does not begin at zero. For the same reason, we cannot make ratios with the values of an interval level variable.
quantitative
Variables that have are measured on a numeric or ________________ scale. -Ordinal -Interval -Ratio scales
tenacity
Wait an hour after eating before you swim which unscientific method of problem solving is this?
cannot
We __________ multiply or divide the values of an interval level variable because it has an arbitrary zero point - interval level measurement does not begin at zero. For the same reason, we ___________________ make ratios with the values of an interval level variable.
Cannot
We _____________ calculate averages because the variables are either qualitative or the distance between the levels of a quantitative variable are not equal. What is your highest level of education? __ Advanced degree __ College graduate __ Some college __ High School graduate __ Some high school __ Jr. High school __ U.N.R. graduate
cannot
We ______________ calculate averages because the variables are qualitative, not quantitative. brown eyes blue eyes green eyes hazel eyes red eyes
tenacity
We are either "left brained" or "right brained" which unscientific method of problem solving is this?
Statistics with nominal level variables
We can calculate the % of occurrences. There were 400 eyes measured 300 brown eyes (75%) 80 blue eyes (20%) 10 green eyes (2.5%) 8 hazel eyes (2%) 2 red eyes (0.5%)
Statistics with ordinal level variables
We can count the number of times each value occurs and create percentages. We can find a middle point (median) because the levels of the variable can be rank ordered.
Statistics with interval level variables
We can count the number of times each value occurs. We can find a middle point (median) because the levels of the variable can be rank ordered. We can add and subtract values We can calculate an average (mean). We cannot multiply or divide the values of an interval level variable because it has an arbitrary zero point - interval level measurement does not begin at zero.
statistic
We need to know the type of variable we are analyzing so we will know the type of _______________ we can use with it. For example, what is the average male height in the U.S.? -Just over 5 ft 9 in. -Height is quantitative and continuous and can be averaged
tenacity
We only use 10% of our brains which unscientific method of problem solving is this?
continuous
Weight discrete of continuous variable?
qualitative and discrete
What is the average eye color in the U.S. ? Eye color is ____________ and _____________ and cannot be averaged. A percentage can be used instead.
D
What is true about the "interval" level of measurement? A. We can make statements about the magnitude of a variable, such as "A 10-milligram dose is twice as much as a 5-milligram dose." B. We can only count the occurrences of the levels of a variable, such as the number of boys and girls in a classroom. C. We can put the various levels of the variable in order, such as the order of finish in a 100-meter dash. D. We can put the various levels of the variable in order, the interval between any two contiguous values is the same, but the starting point for measurement is arbitrary.
B
What is true about the "nominal" level of measurement? A. We can make statements about the magnitude of a variable, such as "A 10-milligram dose is twice as much as a 5-milligram dose." B. We can only count the occurrences of the levels of a variable, such as the number of boys and girls in a classroom. C. We can put the various levels of the variable in order, such as the order of finish in a 100-meter dash. D. We can put the various levels of the variable in order, the interval between any two contiguous values is the same, but the starting point for measurement is arbitrary.
C
What is true about the "ordinal" level of measurement? A. We can make statements about the magnitude of a variable, such as "A 10-milligram dose is twice as much as a 5-milligram dose." B. We can only count the occurrences of the levels of a variable, such as the number of boys and girls in a classroom. C. We can put the various levels of the variable in order, such as the order of finish in a 100-meter dash. D. We can put the various levels of the variable in order, the interval between any two contiguous values is the same, but the starting point for measurement is arbitrary.
A
What is true about the "ratio" level of measurement? A. We can make statements about the magnitude of a variable, such as "A 10-milligram dose is twice as much as a 5-milligram dose." B. We can only count the occurrences of the levels of a variable, such as the number of boys and girls in a classroom. C. We can put the various levels of the variable in order, such as the order of finish in a 100-meter dash. D. We can put the various levels of the variable in order, the interval between any two contiguous values is the same, but the starting point for measurement is arbitrary.
Clearly define the research problem
What should be one of the first steps for a researcher who is planning a research study?
Experimental bias
When a researcher inadvertently (unintentionally) influences subjects' performances, which consequently affects the outcome of a study. This effect is based on research indicating that teachers' expectations can influence student learning. *Threat to internal validity
Selection bias
When the sample that is studied does not represent the population to which the researcher hopes to make generalizations -Using college students in a study targeting military personnel -Using young people in a study targeting old people -volunteer bias and poorly assigning subjects to treatment and control groups *threat to external validity
Statistics
When we draw a sample from a population, we can calculate values called _________________.
C
Why is it important to determine the measurement level of a variable? A. The measurement level will help determine our sampling technique B. The measurement level will tell us how many subjects we need C. The measurement level will lead us to the proper statistics to use D. All of the above
interval scales
______________ _______________ are numeric scales in which we know not only the order, but also the exact differences between the values.
statistic
______________ are numbers that summarize data from a sample. -60% of US residents agree with the latest health care proposal. It's not possible to actually ask hundreds of millions of people whether they agree. Researchers have to just take samples and calculate the rest. -45% of Jacksonville, Florida residents report that they have been to at least one Jaguars game. It's very doubtful that anyone polled in excess of a million people for this data. They took a sample, so they have a statistic. -30% of dog owners poop scoop after their dog. It's impossible to survey all dog owners—no one keeps an accurate track of exactly how many people own dogs. This data had to be from a sample, so it's a statistic.
parameter
_________________ are numbers that summarize data for an entire population. -10% of US senators voted for a particular measure. There are only 100 US Senators, you can count what every single one of them voted. -40% of 1,211 students at a particular elementary school got below a 3 on a standardized test. You know this because you have each and every students' test score. -33% of 120 workers at a particular bike factory were paid less than $20,000 per year. You have the payroll data for all of the workers.
Intuition
_____________________ is a method by which we can "connect" to spiritual things, but it is not recognized by science as a valid method of obtaining universal truths.
Statistics
a mathematical science used in the research process and also in our day-to-day lives may involve: -data collection -data analysis -presentation of data -interpretation or explanation of data
ordinal scale
a scale of measurement in which the measurement categories form a rank order along a continuum
operational definitions
a statement of the procedures used to define research variables Example: The variable "heart rate" will be measured in beats per minute.
Pygmalion effect
higher expectations lead to an increase in performance
discrete
ordinal level measures _________________ variables
Inferential statistics
procedures used to draw conclusions about larger populations from small samples of data
ordinal
rank-ordered finish
Regression toward the mean
research subjects with extreme scores (high or low) on their first attempt will score closer to the mean on their next attempt This assumes that there was luck involved in their first attempt - good luck to those who scored high and bad luck to those who scored low
Estimate
statistics can be used to _______________ parameters.
descriptive statistics
statistics that summarize the data collected in a study
ecological validity
the 'real world' versus the 'experimental world'
external validity
the extent to which the results of a study can be generalized to other situations and to other people
experimental group
the group in an experiment that receives the variable being tested
control group
the group that does not receive the experimental treatment.
Nominal scales
those that use only labels
Inferential statistics
used to draw conclusions about a population based on information contained in a sample. Information is measured from the sample and used to "infer" something about the population.
categorical, qualitative, and discrete
variables at a nominal level of measurement are ____________, __________________, and __________________ in nature. Although numbers may be used to represent the various values of the variables, numbers are treated as labels.
nominal level of measurement
variables whose values have no mathematical interpretation; they vary in kind or quality but not in amount
