LP-7 Flashcards
Causality
Concept that certain exposure will result in a particular outcome.
Correlation
Relationship or association between variables that can be measured mathematically.
Data Analysis
Application of statistical tests to data to organize, describe, summarize, and analyze them to answer a research question or test a hypothesis.
Graphs
Diagram showing the variation of a variable in comparison with one or more other variables.
Inferential statistics
Data generally presented by describing and summarizing them to make inferences or generalizations about a population based on data taken from a sample of that population.
Interpretation
Explanation of results that is used in a research report.
Measures of Central Tendency
Measures used to describe the central tendency of data within a research study
Measures of Dispersion
Identification of how much variation is present in a group of data and description of the distribution of data within a research study.
Normal distribution
curve in which the majority of subjects will fall under the large part of the middle with a few low and high outliers; a bell curve, representing the mean, median, and mode
Null Hypothesis
initial negative statement of belief abut the value of a population parameter, for example that two groups do not differ on as to a variable
Research hypothesis
The logical opposite of the null hypothesis and can indicate a direction of difference
Skewed distribution
Description of distribution of asymmetrical scores causing the curve to be distorted or skewed
What are statistics?
Numeric Characteristics of samples
Science that describes, summarizes, analyzes, and interprets numerical data for purpose of making inferences.
What are biostatistics?
Data analysis and interpretation in health care research.
What should be included in a measurement?
- A clear definition of the variables to be measured.
- Selection of appropriate technique for measurement of the variables.
- Selection of the data collection instrument
- Data collection, analysis, and interpretation
What are the scales of measure?
Nominal
Ordinal
Interval
Ratio
Nominal
organize data collected into mutually exclusive categories and, when a variable can be classified, into two or more mutually exclusive categories relevant to the characteristic being measured. No attempt is made to compare individuals within the categories.
Ordinal
Used to categorize and organize objects or characteristics into mutually exclusive categories and into a rank order based on some criterion. The ordinal scale measures the relative position or rank of objects or individuals with relationship to one another in a group.
Interval
Measures predetermined equivalent intervals, as well as the rank order of the variable measured.
Ratio
The highest level of measurement, as it contains all of the characteristics of the nominal, ordinal, and interval scales in addition to having an absolute zero.
What are two types of statistics?
Descriptive
Inferential
What is descriptive statistics?
Procedures that are used to summarize, organize, and describe quantitative data
There are four characteristics
What are inferential statistics?
Used to make inferences or generalizations about the population
Statistics are a mathematical science of what 3 factors?
- Organizing and summarizing data (descriptive statistics)
- Making decisions with data (inferential statistics)
- Finding relationships between variables with data (correlation)
What is correlation?
A descriptive statistical measure for determining the strength of the linear relationship between two variables.
Measurement
A process that yields quantitative descriptions of the data collected for purposes of analysis and interpretation
Quantitiative
Objective and measurable information, usually numeric
Qualitative
descriptive, explanatory information
What are characteristics of descriptive statistic?
Raw data (info presented in no certain order) Data matrix (Raw data listed lowest to highest) Frequency distribution (division into convenient size classes) Displaying pictorially (graphs)
What are two types of measurements?
Measures of Central Tendency
Measures of Dispersion
What are measures of central tendency?
Mean
Median
Mode
What is mean?
The “average”
What measurement usually accompanies mean to give the most complete data?
Dispersion (standard deviation)
What is the most common used measure of central tendency?
Mean
T or F theoretically and practically, the most important measure of central tendency is mean.
True
How is mean distorted?
Extremely low or high numbers.
What is median?
The “middle”; the numeric value separating the higher half of a sample data set from the lower half.
What are two characteristics of median?
Less reliable for statistical decisions
More stable the the mode
How do you determine median if there is an even number of data?
Take the mean of the two numbers in the middle.
What are characteristics of mode?
- Appears “most frequently”
- Not as widely used
- May not exist or may be more than one
- Not distorted by extremes
What is mode?
The value or values in the data set that occur most frequently.
What are the measures of Dispersion?
Range
Variance
Standard Deviation
What is range?
A comparison of two groups resulting in a judgment.
highest value - lowest value = range
What is variance?
The sum of the squared deviations from the mean, divided by N.
What is the most important measure of dispersion?
Standard Deviation
What is the best summary of data in most cases?
Mean plus the standard deviation.
T or F standard deviation can stand alone.
False
How do you describe the relationship between standard deviation and dispersion?
The greater the dispersion of scores from the mean of the dispersion, the greater the standard deviation.
What are the steps for finding variance and standard deviation?
- Find the mean
- Subtract the mean from each number and square the result.
- Calculate Variance (The sum of all the squared differences added together from step 2)
- Calculate the standard deviation (The square root of the variance)
What does standard deviation help us determine?
How spread out the data values are from the mean.
What does it mean if you have Normal Distribution?
That means the mean equals both the median and the mode
Scores are equally distributed
Bell Curve
What does it mean if the bell curve is positively skewed?
Mean and median are to the right of the mode.
More scores are in the lower range
The bell curve is leaning towards the left.
What does it mean if the bell curve is negatively skewed?
More scores are in the higher range
Mean and median are to the left of mode.
Bell curve leans to the right.
