Unit 2 Vocab
Positive relationship
In a scatterplot, a positive relationship is where the points on the graph are gradually increasing in a linear shape.
Prejudice in favor of or against one thing, person, or group compared with another, usually in a way considered to be unfair.
One variable (X) is called an independent variable or predictor. The other variable (Y), is known as the dependent variable or outcome. What is the simple linear regression equation?
y=B0+B1X
The number of cars in the parking garage.
Quantitative or categorical?
Quantitative
The coefficient of determination, r-squared, tells us:
The percent of variation in "y" that can be explained by the linear model.
Linear Model
An equation that describes a relationship between two quantities that show a constant rate of change.
What does categorical mean?
Unambiguously explicit and direct
Data that represents electricity usage for 135 homes in the month of July is used to create the linear model. The model predicts the amount of electricity used (in kilowatt-hours) based on the size of the home (in square feet).
Predicted Usage = 1204 + 0.6(square feet of home)
Predict the amount of electricity a 2273 square foot home will use according to this model.
2568 kilowatt hours
The height of infants at Baylor Grapevine.
Quantitative or categorical?
Quantitative
What are the 4 methods of data collection? Be sure you can distinguish between them.
Survey, experiment, observational study, and simulation.
The result of the experiment where the explanatory variable is manipulated is a factor whose variation is explained by the other factors. Response Variable is often referred to as the Dependent Variable or the Outcome Variable.
What does quantitative mean?
Relating to, measuring, or measured by the quantity of something rather than its quality
Consider the following statistical studies. Which method of data collection would you use to collect data for each study? (A) A study of the effect of changing flight patterns on the number of airplane accidents.
Simulation (It is impractical to create this situation)
In a recent survey, 1500 adults in the United States were asked if they thought there was solid evidence for global warming. Eight hundred fifty-five of the adults said yes.
What value represents the sample proportion of people who said yes?
1500 adults out of all adults in the US
The data below are the gestation periods, (length of time pregnant) in months, of randomly selected animals and their corresponding life spans, in years. You will use this data set to answer all of the free response questions.
Gestation (months), x
8 , 2.1, 1.3, 1, 11.5, 5.3, 3.8, 24.3
Life Span (years), y
30, 12, 6 , 3, 25, 12, 10, 40
Give the equation for the Least-Squares Regression Line for this data set. Be sure to use good communication.
Life Span = 6.3425 + 1.5229(Gestation)
Least-square regression line slope
The average change in the predicted values of the response variable when the explanatory variable increases by 1 unit.
What is the definition of confounding variables?
It is a third variable that influences both the independent and dependent variables
Given below are five observations collected in a simple regression study on two variables, × (independent variable) and y (dependent variable). X-values and Y-values (2,7) (4,5) (6,4) (8,2) (10,1).
Calculate the intercept b and slope b1, and write down the estimated regression equation.
y=8.30 - 0.75 = 2.30
All 208 passengers on a recent American Airlines flight are asked to rate the level of service as they deplane. 112 say they had excellent service.
112/208 is a: parameter or a statistic?
Statistic
According to the site “High School Census”, 1 in 5 high school students in the state of Texas plays soccer. Assuming this is true, write a simulation to answer this question: If I randomly select 10 Texas high school students, what is the chance that 3 or more of them play soccer? You may describe any method for generating your random numbers. Be sure to describe: 1) Where will your numbers come from? 2) What numbers you will use? 3) What do they represent/are repeats ok? 4) When will you stop? And 5) What will you count from each trial?
I could generate 10 random numbers 1 – 5 using the calculator. If the number is 1 that represents a soccer player. Any other number represents a
non-soccer player. Repeats are okay. Count the number of “soccer players” in your trial of 10
and record. After 20 trials see how many have 3 or more soccer players.
The coefficient of determination (r2)
What is the proportion of the variation in the dependent variable that is predictable from the independent variables.
What is the definition of sampling variability?
How much an estimate varies between samples
A research study finds that fat calories in hamburgers have a positive linear association with the amount of sodium found in the hamburger.
This finding indicates that:
Hamburgers with low amounts of fat calories tend to have low amounts of sodium.
I asked 100 seniors at Grapevine High School if they had a painted parking spot and 65 of them said yes.
Identify the population.
All the seniors at GHS
Did Epstein kill himself?
Was 911 an inside job?
Who framed Roger Rabbit?
Absolutely.
Bill Cosby