In-Class Exercises: How Old is our Solar System?

Astronomy 23/223 In-Class Exercise:

How Old is our Solar System?

In this exercise, we will calculate the age of the igneous rocks that make up the oldest parts of the Moon, which are the anorthosites in the highland areas. The dates we will use came from a paper by Papanastassiou and Wasserburg (1972).

Determine the age of these inclusions by filling in the following worksheet.

Linear Regression the Old-Fashioned Way
(Fill in the Blanks...)

	X Data ⁸⁷Rb/⁸⁶Sr X_i	X_i²	Y Data ⁸⁷Sr/⁸⁶Sr Y_i	Y_i ²	X_i·Y_i
Sample 1	0.03298		0.70127
Sample 2	0.04614		0.70209
Sample 3	0.02414		0.70060
Sample 4	0.17130		0.70954
Sample 5	0.15250		0.70840
Sample 6	0.13800		0.70748
Sample 7	0.13650		0.70758
Sample 8	0.12680		0.70733
Sample 9	0.09050		0.70497
Sample 10	0.07280		0.70373
SUM

= ________ = _________

= average X = ________ = average Y = ________

= _________ = ________

= ________

Now, solve either form of the following two equations, and you'll know the equations of your line!

Equation for regression line is: Y = slope · X + intercept