| 1 |
Editing plots
Lesson
Questions
FOCUS QUESTION: How do I start using MATLAB?
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- Arrays as tables with rows and columns
- Plotting the columns of an array against the integers from 1:n
- Requirements for a well-designed plot
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- MATLAB environment and windows
(Command, History, Workspace, Editor)
- Changing the current directory
- Loading data
- Saving and opening figures
- Edit mode and the plot tools
- Creating and running MATLAB scripts
- Using MATLAB cell mode
- The
plot command
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| 2 |
Working with line graphs
Lesson
Script
Questions
FOCUS QUESTION: How do I display trends in data?
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- Different ways to use line graphs
- Plotting summary information rather than individual data points
- Setting explicit x-axis values using x-y plots
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- Using colons to specify ranges
- Using the linear representation of an array to extract data in a particular order
- The
sum function for adding up rows or columns
- The transpose operator (
') for flipping an array
- Using array division (
./)
- Inserting legends and labels using code rather than by plot editing
- Using
hold on and hold off to display multiple graphs
on the same axis.
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| 3 |
Pie and bar charts
Lesson
Script
Questions
FOCUS QUESTION: How can I show proportions and relative sizes of different data groups?
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- Pie charts for displaying relative proportions
- Bar charts for displaying both proportion and magnitude
- Grouped or stacked bar charts for comparing multiple data sets
- Scaling a data set to make the axes more understandable
- First discussion of color
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- Additional practice with the
sum function
- Using square brackets and commas to assemble an array
- Additional examples of use of transpose and array assembly
- The
pie function for creating a pie chart
- The
bar and barh functions for creating
vertical and horizontal bar charts
- The
stack option of the bar function
- The
colormap function for changing the color scheme of a figure |
| 4 |
Subplots, multiple axes, and insets
Lesson
Script
Questions
FOCUS QUESTION: How can I combine graphs to make effective comparisons? |
- Different strategies for combining plots (insets, subplots and double axis)
- Displaying multiple graphs of different sizes to focus attention
- Overlaying graphs using different scales to compare trends
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- Using the plot-browser to edit and select plots in MATLAB
- The
subplot function for tiling axes
- Creating an inset plot using the insert axis feature
- The
plotyy function for creating a plot with two vertical axes
- Using axis and plot handles to modify graph properties
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| 5 |
Basic statistical indicators
Lesson
Script
Questions
FOCUS QUESTION: How can I find typical characteristics and central tendencies of data?
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- Statistical indicators: mean, median, maximum and minimum
- Outputing information about a data set
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- The
mean, median, max, and min functions
for expressing basic statistical characteristics
- The
fprintf functions for outputting data
- The
linspace function to create an array of equally linearly points
- Developing a function to perform repeated actions on different data
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| 6 |
Scatter plots, curve fitting and correlation
Lesson
Script
Questions
FOCUS QUESTION: How can I determine whether two variables are related?
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- Computing the correlation between two data sets
- Comparing two data sets
by plotting them against each other in a scatter plot
- Computing the best fit line
- Evaluating the RMS (root mean squared) error between predictions and actual data
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- Adding a linear fit line to a scatter plot using the MATLAB plottools
- Constructing strings for plot annotation
- Using
xlabel, ylabel, and title
to directly annotate a plot
- The
corr function for computing correlations
- The
polyfit function for fitting a polynomial to data
- The
polyval function for evaluating a polynomial at an array of points
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| 7 |
Rates of change
Lesson
Script
Questions
FOCUS QUESTION: How can I characterize rates of change?
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- Calculating slope, rate of change, or derivative of data
- Displaying the slope over plotted with the function to
emphasize features
- Plotting data in multiple ranges on the same graph
- Using gridlines to facilitate reading the graph
- Calculating per capita growth rates for comparison in different populations
- Calculating interval midpoints by averaging lower ends with the upper ends
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- The
diff function for computing adjacent differences
- Using a ratio of
diff functions to approximate the slope
- Using
end notation in array index selection
- Dividing a ratio of
diff functions by the population to find
the growth rate per capita or rate of change per capita
- Practicing with concepts of previous lessons
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| 8 |
Vector logic for specializing plots
Lesson
Script
Questions
FOCUS QUESTION: How can I extract the rows and columns of an array based on data characteristics?
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- Using logical operators to pick out subsets of the data
- Using relational operators to compare data and set ranges
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- Using logical operators
& (and), | (or), ~ (not)
to express conditions on the data
- Using vector indexing (logical vectors as array indexes) to select rows or columns
- Using relational operators
< (less than), <= (less than or equal),
> (greater than), >= (greater than or =),
== (equal), and ~= (not equal) to compare data values.
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| 9 |
Program control
Lesson
Script
Questions
FOCUS QUESTION: How can I execute different code depending on the data?
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- Coin tossing and random walk
- Keeping a running sum to find totals
- Expressing alternative actions
- Repeating actions under slightly different conditions
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- Using the rand function to pick a value at random
- Using if and if-else to express alternative actions
- Using for to repeat a set of actions
- The find function for discovering the position of particular values
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| 10 |
Histograms
Lesson
Script
Questions
FOCUS QUESTION: How can I understand and compare the distributions of two data sets? |
- Using histograms to convey distribution characteristics
- Computing the cumulative probability distribution
- Comparing the characteristics of common distributions (normal, uniform and exponential)
- Scaling histograms to show the fraction of values rather than the number of values
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- The
hist function for computing frequency tables
- The
stairs function for displaying a stair plot
- Setting the number of bins and bin positions for a histogram
- The
random function for generating pseudo-random values from
a specified distribution |
| 11 |
Box plots
Lesson
Script
Questions
FOCUS QUESTION: How can I compare the distributions of data sets that have outliers?
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- Comparing distributions using box plots
- Computing relative data set sizes
- Observing medians and IQRs
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- The
boxplot function for showing distributions
- Using labeled data in box plots
- Other variations of the box plots
- The
repmat function
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| 12 |
Error bars
Lesson
Script
Questions
FOCUS QUESTION: How can I depict uncertainty and variability in data?
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- Using error bars to depict spread
- Using error bars on bar charts
- Computing and interpreting standard error of the mean (SEM)
- Creating SD, SEM and IQR error bars
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- The
errorbar function and its variations
- Using
gca to get and set axis properties
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| 13 |
Depicting confidence
Lesson
Script
Questions
FOCUS QUESTION: How reliable is my estimate of population mean?
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- Using error bars to depict confidence intervals
- Averaging to extract trends and reduce noise
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- Using reshaping arrays to average in different ways
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| 14 |
Tests for normality or other distributions
Lesson
Script
Questions
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- Testing for normality through visual and computational tests
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- The
normplot function for visually testing normality
- The
lilliefors function to test for normality
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| 15 |
Hypothesis testing
Lesson
Script
Questions
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- Formulating a testable hypothesis
- One-sided and two-sided hypothesis tests
- Understanding significance levels and p-values
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- The
ttest for testing population mean
- The
ttest2 for comparing population means
- Using p-values and confidence intervals to obtain additional detail
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| 16 |
Logarithmic scales
Lesson
Script
Questions
FOCUS QUESTION: How can I use logarithmic scales to understand rates of growth?
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- Calculating slope of data expressed on linear and logarithmic scales
- Plotting data on various types of logarithmic axes
- Examining rates of growth
- Performing a linear fit and finding the R2 to characterize the quality of the fit.
- Finding per capita growth rates
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- The
semilogx and semilogy functions
- The
loglog function
- Examining rates of growth
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| 17 |
Modeling the heart
Lesson
Script
Questions
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| 18 |
Working with dates
Lesson
Script
Questions
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| 19 |
Input and output
Lesson
Script
Questions
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