Today we spent more time looking at linear regression. We did the following workshop in class.
Today we reviewed for the midterm exam on Friday. We went over some of the review problems, and we did the following extra problems in class.
The Columbus Dispatch did a test to see if a football filled with helium travels farther on average when kicked than a regular football. A volunteer kicker kicked a ball filled with helium 39 times and also kicked a regular football 39 times. On average, the helium filled football traveled 0.46 yards farther per kick.
What are the individuals in this study?
What is the parameter of interest?
What is the sample statistic?
Was this an experiment or an observational study?
Heights for men in the United States are normally distributed with a mean of μ = 70 inches and a standard deviation of σ = 3 inches.
What is the percentile of a man who is 5’5" (65 inches) tall?
How tall would a man who is in the top 5% be?
The average height for students in our class is x̄ = 71.25 inches with a standard deviation of sx = 2.91 inches. The average weight is ȳ = 179.6 lbs. with a standard deviation of sy = 22.6 lbs. The correlation between height and weight is R = 0.227.
Use the formula y = m x + (ȳ - m x̄) where m = R(sy/sx) to find the equation for the linear regression line for predicting the weight of HSC students based on their height.
What is the slope (including units) for the regression line?
Use the regression line to predict the weight of a student who is 76 inches tall.