80 likes | 314 Views
Correlation Mini Project. Michelle Han Period 1. Hours of sleep VS. First period grades. Hours of sleep. First period grades. Hours of sleep. First period grades. Is there a correlation between the hours of sleep a student gets on average and their first period percentage grades?
E N D
Correlation Mini Project Michelle Han Period 1
Hours of sleep VS. First period grades Hours of sleep First period grades Hours of sleep First period grades • Is there a correlation between the hours of sleep a student gets on average and their first period percentage grades? • A sample size of 30 students were asked.
LSRL (Least Square Regression Line) • Also known as Line of best fit Linear Model Linear Equation Regression Equation y= first period percentage x= hours of sleep First period percentage= (.39462) + (.06349)(hours of sleep) Linear Regression y = a + bx a= .3946232135 b= .0634863577 r2= .7512241435 r= .8667318752
R and R-Squared in Context • R is the correlation coefficient • Measures the scatter around the line • Strength of association between x & y • When r is .7 or better, it’s strong • When r is .4-.6, it’s moderate • When r is .3 and below, it’s weak R R- Squared There is a strong, positive linear association between hours of sleep and first period grades. 86.7% of the variation in the first period grades can be explained by the approximate linear relationship with hours of sleep.
Predictions • Make a prediction for some who slept 10 hours using the model. • First period grade = .39462 + .06349 (10 hours) First period grade= .39462 + .6349 First period grade= 100.02 Our model predicts a first period grade of 100.02% if a student slept for 10 hours.
Y-Intercept and Slope • Y-Intercept (a): Always plug in 0 as x. • Slope (b): Y-units Slope: For every hour of sleep, our model predicts an average increase of .06349 in the first period grade. Y-Intercept: If you sleep 0 hours, our model predicts a first period grade of .39462
Residual Plot The points are residuals. The line is a prediction. No pattern/residuals are randomly scattered = a good fit Because the points or residuals are randomly scattered throughout the plot, our modes is a good fit.