Ch. 1 Inferential Statistics
What 2 types of Classifications does Quantitative Variables have?
Discrete and Continuous Variables
Descriptive Statistics
Methods of organizing, summarizing and presenting data in an informative way (simple data not analyzed, uses lots of numbers)
Interval Level
Similar to the ordinal level, with the additional property that meaningful amounts of differences between data values can be determined. There is no natural zero point ( temp. On the Fahrenheit scale) quantitative variable"
Single blind experiment
Subjects do not know if they are in a control or treatment group but the testers do
What are variables contributing to confounding variables?
Treatment, subjects, gender, height, allergies, placebo affect
What are the properties of the Interval Level?
1. Data classifications are ordered according to the amount of the characteristic they possess 2. Equal differences in the characteristic are represented by equal differences in the measurements Ex: woman's dress sizes listed on a table graph
Population
A collection of ALL possible individuals, objects or measurements of interest
What are the 4 types of studies?
1. Cross sectional 2. Longitudinal 3. Meta- Analysis 4. Case Study
Placebo effect
A response to the power of suggestion rather than the treatment itself by participation of an experiment
Inferential Statistics
A decision, estimate, prediction or generalization about a population based on a sample (inquiring more info)
Control group
A group of subjects to which no treatment is applied in an experiment
Treatment group
A group of subjects to which researchers apply a treatment in an experiment
Sample
A portion or part of the population of interest
Meta-analysis
A study that complies information from previous studies
Case study
A study that looks at multiple variable that affect a single event
Cross- sectional study
A study where data is collected at a single point in time Ex: polls and surveys
Longitudinal study
A study where data is gathered by following a particular group over a period of time Ex: national longitudinal study of adolescence health over 14 years
Placebo
A substance that appears identical to the actual treatment but contains no beneficial elements
Continuous Variables
Can assume any value within a specific range (any number) ex: the pressure in a tire
Discrete Variables
Can only assume certain values and there are "usually" gaps between values ( must be whole numbers)
Bias
Choosing a particular portion directly or indirectly
Confounding variables?
Factors that can alter an experiment
Quantitative Variable
Information is reported (Numerically) ex: amounts, number of children in a family, minutes remaining in a class (interval level)
Statistics
Is the science of collecting, organizing, presenting, analyzing, and interpreting numerical data to assist in making more effective decisions
Qualitative or attribute Variables
The characteristic being studied is (Non-numeric) ex: gender, eye color, state of birth etc. (nominal level)
Ratio Level
The interval level with an inherent zero starting point. Differences and ratios are meaningful for this level of measurement ( monthly income of surgeons)
Why is it important to know the levels of measurement?
1. Because it dictates the calculations that can be done to summarize and present the data 2. To determine the statistical tests that should be performed on the data
What are the properties of the Ratio Level?
1. Data classifications are ordered according to the amount of the characteristics they possess 2. Equal differences in the characteristic are represented by equal differences in the numbers assigned to the classifications 3. The zero point is the absence of the characteristic and the ratio between two numbers is meaningful
What are the properties of the Ordinal Level?
1. Data classifications are represented by sets of labels or names ( high, medium, low) that have relative values 2. The data classified can be ranked or ordered due to the relative values
What are the properties of Nominal Level?
1. Observations of the qualitative variable can only be classified and counted 2. There is no particular order to the labels
What are the components of the Scientific Method?
1. State the problem 2. Formulate a hypothesis 3. Perform experiment 4. Collect data ( using 1 of the 4 levels measurement 5. Make a conclusion (statistics)
What are the 4 types of Experimental Groups?
Control Treatment Single blind Double blind
Ordinal Level
Data arranged in some order but the differences between data values can not be determined or are meaningless ( abc order)
Nominal Level
Data that is classified in categories and can not be arranged in any particular order ( eye color, gender, religion, name) "qualitative variable"
What are the 2 types of statistics?
Descriptive and Inferential
Double blind experiment
Neither subject nor testers know to which group each subject belongs
What are the 4 levels of measurement?
Nominal, Interval, Ordinal and Ratio level
What are 2 types of Variables
Qualitative and Quantitative
Practically all quantitative data is recorded on what level of measurement?
Ratio Level
What is the "highest" level of measurement?
Ratio Level