Statistics Chapter 3 Exam Questions And Answers 100% Pass
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Course
Statistics
Institution
Statistics
Statistics Chapter 3 Exam Questions And
Answers 100% Pass
Procedure with 2 variable statistics - answer1.) Plot data and calculate numerical summaries
2.) Look for overall patterns and deviations from those patterns
3.) When there's a regular overall pattern, use a simplified model to describe ...
Statistics Chapter 3 Exam Questions And
Answers 100% Pass
Procedure with 2 variable statistics - answer✔1.) Plot data and calculate numerical summaries
2.) Look for overall patterns and deviations from those patterns
3.) When there's a regular overall pattern, use a simplified model to describe it
Response variable - answer✔Measures an outcome of a study
Explanatory variable - answer✔May help explain or influence changes in a response variable
Specific values of variables - answer✔It is easiest to identify explanatory and response variables
when we actually specify values of one variable to see how it affects another variable.
Causation - answer✔Often we want to know whether changes in the explanatory variable
causes a change in the response variable. Remember, correlation does NOT imply causation.
Graph for displaying relationship between two quantitative variables - answer✔Scatterplot
Scatterplot - answer✔Shows the relationship between two quantitative variables measured on
the same individuals. The values of one variable (explanatory variable) appear on the horizontal
axis and the values of the other variable (response variable) appear on the vertical axis. Each
individual in the data appears as a point in the graph.
Explanatory-response relationship - answer✔Always plot explanatory variable if there is one on
horizontal axis (x axis) of the scatterplot. We usually call the explanatory variable x and the
response variable y. If there is no explanatory-response distinction, either variable can go on
the horizontal axis.
How to make a scatterplot - answer✔1.) Decide which variable should go on each axis
2.) Label and scale your axes
- Don't start at (0,0)
- Start scale to highlight main body of points
3.) Title your plot
4.) Plot individual data values
How to examine scatterplots - answer✔Look for the overall pattern and striking departures
from that pattern.
1.) To describe the OVERALL PATTERN of a scatterplot, discuss the direction/trend, the
form/shape, clusters and the strength of the relationship
2.) To describe DEPARTURES from the OVERALL PATTERN discuss outliers (an individual that
falls outside the overall pattern of the relationship)
Form/shape - answer✔The general shape of the graph
Ex: linear relationships/curved relationships/outliers/clusters
Direction/trend - answer✔Draw oval around data and find the slope of the major axis: negative
slope means negative trend while positive slope means positive trend
If relationship has a clear direction, we speak of positive association (high values of one variable
tend to occur together) or negative association (high values of one variable tend to occur with
low values of the other variable)
Strength (heteroscedasticity) - answer✔How scattered is the data (based on the oval)
How close the points in a scatterplot lie to a simple form such as a line
- Thin hot dog shape = strong
- Football shape = moderate
- Basketball shape = week
- Fan out = differs for different values of explanatory variable
*Correlation coefficient
Cluster - answer✔There are a bunch of data points together
- Name ranges of each variable where cluster appears
Outlier - answer✔There's a lot of white space around the data point
- Outlier in response variable (y)
- Outlier in explanatory variable
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