Basic Concepts and Definitions, Data, Presentations Flashcards
2 Categories of Statistics?
Descriptive statistics and inferential statistics
Descriptive statistics?
Inferential statistics?
DS- collection, organization, summarization and presentation of data
IS- drawing of inferences about a larger group of data from a sample of the data
Data?
raw material of statistics, usually defined as numbers
2 types of numbers used in statistics come from?
taking of a measurement and the process of counting
Variable?
characteristic that takes on different values in different persons, places or things
Dependent Variable?
outcome of interest, should change in response to some intervention
Independent Variable?
intervention, what is being manipulated. variable that has an effect on the dependent variable
Quantitative variable?
one that can be measured
Qualitative variable?
cannot be measured. should be categorized
Discrete variable?
has numbers that can assume only whole numbers (ex; eye colour, head hairs lost, hospital visits)
Continuous variable?
may take any value within a defined range (ex; height, weight, BP)
Random variable values?
obtained as a result of a chance factor, not predicted in advance
Nominal Scale?
simplest type of data, values fall into unordered categories
-categories are mutually exclusive
Are nominal values continuous or discrete?
discrete
Numbers in the nominal scale?
used to distinguish b/w categories, has no mathematical meaning
Ordinal Scale?
observations can be put into categories and can be ranked according to some criterion
Are ordinal scales continuous or discrete?
discrete
Numbers in the ordinal scale?
have no mathematical meaning and are used to distinguish b/w categories
The interval scale?
not only possible to order measurements, but also the distance b/w any 3 measurements is known
distance b/w measurements are equal
Are interval scales continuous or discrete?
continuous
“zero” in the interval scale?
may not necessarily mean a true zero
numbers and ratios in the interval scale?
differences b/w numbers are meaningful, ratios b/w numbers are not
The ratio scale?
highest level of measurement
“zero” in the ratio scale?
can be a true zero
Are ratio variables continuous or discrete?
continuous
Intervals and ratios in the ratio scale?
both meaningful
Absolute frequency?
number of things in a category/ count
Relative frequency?
percentage of the total
Bar graphs? Y axis=? X axis=?
best at comparing two or more groups
Y axis= frequency
X axis= stage/ category
Do histograms have continuous or discrete variables? how can you tell?
continuous
bars are put together and not spread apart
When is it good to use a scatter plot?
when you have 2 continuous variables to identify the difference
Which scale does scatterplots use and why?
Ratio scale. relationship b/w two things
Do steam and leaf plots have discrete or continuous variables?
continuous
Q2=? (thick line)
Q1=?
Q3=?
IQR=?
Q2= median Q1= 25% of data is bellow this line (75 is above this line) Q3= 75 percent of the data is bellow this line (25% is above this line) IQR= Q3-Q1 (difference b/w Q1 and Q3
What type of data sets would you use box and whisker plots for?
continuous data sets
