Discussion:
Q1. For the first set of paired data:
a) Make a scatterplot of the data.
b) Use Excel functions to find the means and standard deviations of each variable.
c) Working in Excel, calculate the correlation coefficient (r) by creating columns of calculations (unpack the formula).
d) Find the regression equation relating the variables. Use the first column as the explanatory variable and the second as the response variable.
e) What y-value would you predict from x = 58 in the data set? Why?
| x |
y |
| 4 |
91 |
| 21 |
127 |
| 26 |
28 |
| 20 |
59 |
| 18 |
173 |
| 51 |
206 |
| 48 |
101 |
| 40 |
126 |
| 37 |
242 |
| 35 |
291 |
| 29 |
219 |
| 52 |
262 |
| 54 |
355 |
| 60 |
392 |
| 68 |
324 |
| 38 |
314 |
| 70 |
323 |
| 46 |
347 |
| 60 |
419 |
| 62 |
507 |
Q2. For the second data set, do the following:
a) Make a scatterplot of the data.
b) Use Excel functions to find the means and standard deviations of each variable.
c) Find the regression equation relating the variables. Use the first column as the explanatory variable and the second as the response variable.
d) What y-value would you predict from x = 58 in the data set? Why?
| x |
y |
| 47 |
38 |
| 62 |
62 |
| 65 |
53 |
| 70 |
67 |
| 70 |
84 |
| 78 |
79 |
| 95 |
93 |
| 100 |
106 |
| 114 |
117 |
| 118 |
116 |
| 124 |
127 |
| 128 |
114 |
| 140 |
134 |
| 140 |
139 |
| 140 |
142 |
| 150 |
170 |
| 152 |
149 |
| 164 |
154 |
| 198 |
200 |
| 221 |
215 |