Statistics|Mathematics
The correlation coefficient, rr, is a number between
· 0 and ∞∞
· 0 and 1
· -1 and 1
· 0 and 100
· −∞-∞ and ∞∞
· 0 and 10
· -10 and 10
A correlation of r = .85 is found between weekly sales of firewood and cough drops over a 1-year period. Which of the following is true?
· (a) There is a pretty strong positive linear relationship between sales of firewood and cough drops.
· (b) Fire must be the cause of coughing.
· (c) Temperature is a possible lurking variable that is “behind” this relationship.
· (d) Both (a) and (c) are true.
· (e) None of the above.
Annual high temperatures in a certain location have been tracked for several years. Let XX represent the year and YY the high temperature. Based on the data shown below, calculate the correlation coefficient (to three decimal places) between XX and YY.
| x | y |
| 2 | 11.64 |
| 3 | 12.81 |
| 4 | 15.78 |
| 5 | 18.35 |
| 6 | 17.22 |
| 7 | 21.59 |
| 8 | 25.56 |
| 9 | 25.63 |
| 10 | 29.3 |
| 11 | 31.47 |
r=r=
Box 1: Enter your answer as an integer or decimal number. Examples: 3, -4, 5.5172 Enter DNE for Does Not Exist, oo for Infinity
Annual high temperatures in a certain location have been tracked for several years. Let XX represent the year and YY the high temperature. Based on the data shown below, calculate the regression line (each value to two decimal places). y = x +
| x | y |
| 2 | 15.18 |
| 3 | 13.52 |
| 4 | 12.56 |
| 5 | 9.4 |
| 6 | 10.24 |
| 7 | 9.78 |
| 8 | 7.32 |
| 9 | 4.26 |
| 10 | 4.5 |
Get help: Video
Box 1: Enter your answer as an integer or decimal number. Examples: 3, -4, 5.5172 Enter DNE for Does Not Exist, oo for Infinity
Box 2: Enter your answer as an integer or decimal number. Examples: 3, -4, 5.5172 Enter DNE for Does Not Exist, oo for Infinity
The table below shows the number of state-registered automatic weapons and the murder rate for several Northwestern states.
| xx | 11.4 | 8.5 | 6.6 | 3.6 | 2.4 | 2.7 | 2.5 | 0.3 |
| yy | 13.5 | 11.3 | 9.3 | 6.8 | 5.8 | 6.4 | 6.1 | 4.5 |
xx = thousands of automatic weapons yy = murders per 100,000 residents This data can be modeled by the equation y=0.83x+4.02.y=0.83x+4.02. Use this equation to answer the following; Special Note: I suggest you verify this equation by performing linear regression on your calculator. A) How many murders per 100,000 residents can be expected in a state with 8.4 thousand automatic weapons? Answer = Round to 3 decimal places. B) How many murders per 100,000 residents can be expected in a state with 8.7 thousand automatic weapons? Answer = Round to 3 decimal places.
