Biostatistics Basics Flashcards
What are the 2 types of variables?
Independent
Dependent
Independent variables precede dependent variables in what?
Time
What variable can be manipulated by the researcher?
Independent
The treatment or intervention is what variable?
Independent
The dependent variable depends on what?
Independent Variable
What is the group from which a sample is drawn?
Population
What is a subset of a population?
Sample
What type of samples are representative of the source population?
Random Samples
Random assignment is also known as?
Randomization
What is a way to summarize data from a sample or a population?
Descriptive Statistics
Descriptive statistics illustrate what of a set of data?
Shape
Central Tendency
Variability
The shape of the data involves frequencies of what?
Values of observataions
Central tendency means the location is where?
Middle of the data
Variability refers to?
Spread
Dispersion
What visually depict frequency distributions of continuous data?
Histograms
What are used to depict categorical information?
Bar Charts
What is the most common descriptive statistic?
Mean (average)
What is the most frequently occurring value in a series?
Mode
The value that divides a series of values in half when they are all listed in order is known as what?
Median
What are the 4 levels of measurement?
N-Nominal (name/label)
O-Ordinal (ordered rank)
I-Interval (equal intervals)
R-Ratio (true zero)
What are often symmetrical with most scores falling in the middle and fewer toward extremes?
Distributions
Most biological data are symmetrically distributed and form what?
Normal Curve (bell-shaped curve)
The area under a normal curve has what?
Normal Distribution
What are some properties of a normal distribution?
Symmetric about it’s mean
Highest point is at mean
Height of curve decreases as one moves away from mean in either direction, never reaches zero.
What does it mean when there is a skewed distribution?
Mean, median and mode are not equal and are in different positions.
Skew is always toward the direction of which tail?
Longer Tail
+ = Right
- = Left
What is a better estimate of the center of skewed distributions?
Median (central point of distribution)
What is a measure of the variability of a set of data?
Standard Deviation
The range of scores is referred to as?
Variability or Spread
What is the number of standard deviations that a specific score is above or below the mean in a distribution?
Z-Scores
The proportion of scores that are higher or lower than a specific z-score can be determined by referring to?
z-table
