1 / 3

What is Pearson’s coefficient of correlation?

The dependent (y) variable is average SAT score; the independent (x) variable is average class size. Data are for the 50 states and DC. What is Pearson’s coefficient of correlation? What proportion of the variation in SAT scores is explained by variation in class sizes?

tomai
Download Presentation

What is Pearson’s coefficient of correlation?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The dependent (y) variable is average SAT score; the independent (x) variable is average class size. Data are for the 50 states and DC. • What is Pearson’s coefficient of correlation? • What proportion of the variation in SAT scores is explained by variation in class sizes? • What is the regression equation? • If class size is reduced by an average of one student, what will be the impact on SAT scores? • Is there a significant relationship between class size and SAT scores? • What test did you perform to answer 5 and what is the p-value of the test?

  2. What proportion of the variation in SAT scores is explained by variation in bachelors’ degrees? • What is the standard error of the estimate sy.x? • Predict the average SAT score in a state in which 20% of the population hold bachelors’ degrees. • What is the t statistic for the test H0: 1 = 0? What is the p-value of the test? • At 5% significance should you reject H0? Is there a statistically significant relationship between SAT and Bachelor? The independent (x) variable is the percentage of each state’s population who have at least a bachelor’s degree.

  3. The independent (x) variable is Law Enforcement Officers per 1000 population (LO); the dependent variable is violent crimes per 1000 population (VC). Data are for 97 NC counties. • What is the correlation coefficient between LO and VC? • What proportion of the variation in crime is explained by variation in the number of law enforcement officers? • What is the regression equation? • Predict the crime rate for a county that has 5 law enforcement officers per 1000 population. • Give a 95% confidence interval for the crime rate in all counties with LO = 5. Assumex = 2.7 and that t95 = 2. • Give a 95% prediction interval for the crime rate in a county in which LO = 3 using the same assumed values as in q. 5. • Give a 95% confidence interval for the value of 1. • Is there a significant relationship between LO and VC? • What hypothesis test did you perform to answer question 7? What was the p-value of the test? • Would this regression analysis support the theory that law enforcement officers tend to cause crime?

More Related