Download Class Outline - HCC Learning Web

ENGINEERING 2304
Computer Programming for Engineers
ENGR 2304-56619 Summer 2015
Class 5
Class Outline
• Quiz
• Review Homework
• Plotting Equations
• Plotting Data
• Statistical Tools
• Histograms
• Practice Exercises
Class 5Quiz
• Pull out a sheet of paper and solve the following problems:
1. According to the US Census Bureau, in 2000, there were 20,851,820
people living in the state of Texas. In 2010, there were 25,145,561. Use
linear interpolation to estimate the population, to the nearest person, in
2007.
2. Find the mean, median, mode and range of the following data set:
13, 29, 12, 15, 12,
13, 42, 17, 13, 18
23, 12, 15, 20, 13
3. Graph the equation 3x-4y=15.
Quotes of the Day:
“There are three kinds of lies: lies, damn lies, and statistics.” –Mark Twain, 1906
"The statistics on sanity are that one out of every four Americans is suffering
from some form of mental illness. Think of your three best friends. If they're
okay, then it's you.”–Rita Mae Brown
“One of the first things taught in introductory statistics textbooks is that
correlation is not causation. It is also one of the first things forgotten.”
-Thomas Sowell
Homework Questions
Plotting Equations: Data Points and Linear
Regression
• Scatter Plots: A simple Cartesian X-Y
plot of a dependent and independent
variable. Independent: x-axis.
Dependent: y-axis.
• All scatter plots should have:
• Title
• Labeled Axis with Units
Linear Regression: Trend Lines
• Trend lines or best fit line
• Can use linear, quadratic,
exponential, etc regression.
• For simple linear regression:
α = 𝑦 − β𝑥
Correlation
Strong Correlation
Weak Correlation
R^2: correlation coefficient
Presenting Single-Variable Data: Pie Charts
Pie Charts:
• Simple statistical graph
• Divided into regions, arc length/angle
corresponds to percent of total.
• Often a poor choice, as the viewer
cannot easily tell the exact values of
data. Only a rough tool at best.
Presenting Single-Variable Data: Bar Charts
• Bar charts present values of a category on a labeled axis. Usually superior to a pie chart.
Single-Variable Statistical Tools
• Mean: Sum of data over the number of data points.
• Median: When arranged least to greatest, the middle term.
For an even number of terms, the mean of the two middle
terms.
• Mode: The most common value in a set.
• Range: Greatest minus the least
• Standard Deviation: A measure of how far from the mean, or
how “spread out” the data is.
Histograms
• Group data in to ranges, or “bins.”
• Height of graph of each bin is the number in the bin,
(referred to as frequency) or a percent of the whole.
Cumulative Histograms
Example 1: Linear Scatter Plot and Interpolation
Exercise
Example 2: Quadratic Scatter Plot and
Regression
Example 3: Exponential Regression, Moore’s Law
Example 4: Pie Charts and Bar Charts
• Data for January 2015 US Auto Sales
• Create a pie and bar chart for this data.
Example 5: Statistical Analysis: Height
• Find mean, median mode, and range for class height data.
• Create a histogram of this data.