Statistics of Two Variables

1. JEOPARDY Statistics of Two Variables

2. Statistics of Two Variables

3. Topic 1: 200 • Question: • Variables have a ______ ______ if changes in one variable tend to be proportional to changes in the other. • Answer • Linear Correlation Back

4. Topic 1: 400 • Question: • Interpret the following “r” values and state their correlation.1. 0.75 2. -0.46 3. 0.15 • Answer • 1. Strong Positive Linear Correlation • 2. Weak Moderate Linear Correlation • 3. Weak Positive Linear Correlation Back

5. Topic 1: 600 • Question: • On the chalkboard; write down the formula to find Correlation Coefficient (r) • Answer Back

6. Topic 1: 1000 • Question: • Sum of all:n=6 x=63 y=433 x²=731 y²=32155 xy=4736Find “r”(Must show all work) • Answer • r=0.755 Back

7. Topic 2: 200 • Question: • ______ is an analytic technique for determining the relationship between a dependent variable and an independent variable. • Answer • Regression Back

8. Topic 2: 400 • Question: • On the chalkboard; write down the formula to find Least Squaresa=? b=? • Answer Back

9. Topic 2: 600 • Question: • Sum of all:n=7 x=371 y=348 x²=26401 xy=22602Find “a”(Must show all work) • Answer • 0.615 Back

10. Topic 2: 1000 • Question: • Sum of all:n=6 x=36 y=921 x²=226 xy=5127Perform a linear regression to find the LOBF • Answer • y=-39.9x + 392.9 Back

11. Topic 3: 200 • Question: • The _____ __ _____, r², is a number which describes how closely the points follow the curve of best fit (COBF) • Answer • Coefficient of Determination Back

12. Topic 3: 400 • Question: • Use a graphing calculator to find the equation and coefficient of determination “r²” for a curve of best fit. • Answer • y= - 1.43x² - 2.46x + 4.64; r² = 0.966 Back

13. Topic 3: 600 • Question: • Use a graphing calculator to find the equation and coefficient of determination “r²” for a curve of best fit. • Answer • y= 0.89x³ + 3.68x² + 3.29x + 1.01; r² = 0.959 Back

14. Topic 3: 1000 • Question: • Use a graphing calculator to find the equation and coefficient of determination “r²” for a curve of best fit. • Answer • y=1.60(1.77)^x or y=1.60(e^0.57x);r²=0.979 Back

15. Topic 4: 200 • Question: • A change in X produces a change in Y.What kind of a relation is this? • Answer • Cause-and-Effect relationship Back

16. Topic 4: 400 • Question: • The dependent and independent variables are reversed in the process of establishing causality. • Answer • Reverse Cause-and-Effect relationship Back

17. Topic 4: 600 • Question: • Classify the relation in both situations1. The rate of a chemical reaction increases with temperature.2. Leadership ability has a positive correlation with academic achievement. • Answer • 1. Cause-and-Effect relationship2. Presumed relationship Back

18. Topic 4: 1000 • Question: • In order to reduce the effect of extraneous variables, researchers often compare an _____ _____ to a _____ _____. • Answer • Experimental Group; Control Group Back

19. Topic 5: 600 • Question: • A teacher is trying to determine whether a new spelling game enhances learning. In his gifted class, he finds a strong positive correlation between use of the game and spelling-test scores. Should the teacher recommend the use of the game in all English classes at his school? • Answer • No. D:< Back

20. Topic 5: 1000 • Question: • You must be careful about accepting statistical results from sources that are biased or flawed, unintentionally or intentionally.Explain 3 things you would most likely critically examine. • Answer • Source of the data;Sampling;Analysis techniques applied;Motivations & agenda of the author. Back

21. Bonus Question: 2500 pts. • Question: • The covariance divided by the product of the standard deviations for X and Y equals to…? • Answer • Correlation Coefficient, “r” Back