Week 1 Flashcards
What is a constant ?
Does not change in value
What is a variable ?
has more than one value
What is a discrete variable ?
only takes on whole-valued numbers
What is a continuous variable?
falls in a continuum and allows fractional amounts
What are the 4 scales of measurement ?
- Nominal
- Ordinal
- Interval
- Ratio
What is a nominal scale ?
broken into categories that have no numerical properties
What is a ordinal scale ?
broken into categories on a ranked order
What is a interval scale ?
number-based, distance b/w numbers in this scale is equal
What is a ratio scale ?
also number-based and equal distance b/w interval but has an absolute zero - when the number 0 menas that this variable doesn’t exist
What is random sampling ?
every member of the population has an equal probability of being included into the sample. This is the basis of all statistics!
What are the 2 branches of statistics ?
- Descriptive - Homogeneity of performance
- Inferential - probability-based
What are the 3 goals of scientific research ?
- to DESCRIBE - Observational studies, case studies, surveys
- to PREDICT - correlational studies; quasi-experimental
- to EXPLAIN - experimental studies
What is the purpose of correlational studies ?
To predict the association or relationship b/w two variables
What is the symbol used to depict correlation ?
r
* sign = direction
* value = strength/magnitude
What is a confound variable ?
A third variable that may indirectly impact the 2 variables in a correlational study
What is the purpose of experimental studies ?
to determine cause-and-effect relationship b/w variables
What is a dependent variable ?
what is being measured and compared
What is a independent variable ?
what you manipulate
What is a control group(s) vs a experimental group(s) ?
- Control - didn’t receive any levels of IV
- Experimental - received some levels of IV
What are control variable(s) ?
variables that you want to make sure is the same b/w different groups
What is involved in quasi-experimental studies ?
- When the variable of interest is not manipulated by the researcher
- cannot offer causal explanation
What is the mean ?
the arithmetic average in a set of data
What is the issue with the mean ?
the mean is very sensitive to EXTREME scores in the dataset
What is the median ?
the middle score in the distribution, when the scores are sorted in ascending or descending orders
What is the mode ?
the score that occurs with the greatest frequency
What is variability ?
the dispersion of scores
What is range ?
- the difference b/w the lowest and the highest score in a distribution
- prone to the impact of extreme scores
What is interquartile range ?
Difference b/w the 75th and 25th centile in a distribution
What is averge deviation ?
- indicated the avg difference b/w the scores in a distribution and the mean of the distribution
- uses the absolute values to indicate the distance
What is deviation ?
the difference b/w the score and the mean
What is standard deviation ?
the sqaure root of the averged SS (sum of squared deviations) from the mean
What is a normal curve ?
a symmetrical, bell-shaped frequency polygon representing a normal distribution
What is a raw score ?
the acutal value of a score
What is a z score ?
the standard score, which indicates how many SD units a raw score is from the mean of the distribution
