Module 2 Flashcards
type of data used for a bar graph
categorical
explain skewness of a histogram
negative skewed means the left has the tail, positive skewed means the right has the tail
histogram modality
unimodal, bimodal and multimodal
best measure of central tendency for when data is skewed
median
frequency polygon
basically a histogram but x axis marks mid point of each interval, useful for comparing multiple groups
one way scatter plot
categorical or scale data, all observations represented as a single point (can be hard to read at times)
two way scatter plot
relationship between two scale variables
box plot
categorical or scale, shows summary of data and any extreme values
how to calculate outliers
- value is more than 2 SD above/ below the mean
- Q1 - (1.5)(IQR)
- Q3 + (1.5)(IQR)
line graph
relationship between two scale variables, each point on the x axis has to have a corresponding y value which is not a requirement for a scatter plot
outliers keep or remove
keep if genuinely obtained
- another factor impacting outcomes
- random chance, theoretically possible but highly unlikely
- gives insight into a new phenomenon
remove is related to an error
- data entry error, typo
- process error, issues with data collection
what is a population
group of objects, events, people, procedures, observations a researcher is interested in studying
what is a sample
subset of data included in a study
types of sample approaches
random - each item of interest has an equal chance of being included
non random - items included selected for a reason
sampling bias
members/items of a population don’t have a fair chance of being in the study
