It is now linear regression time. LINEST is an easy option. The format in OpenOffice is LINEST(data_y;data_x;linear_type;stats). For data_y, highlight the cells for ln Cp. For data_x, highlight the cells for time. For linear_type, enter a 1. For stats, enter a 0. Remember to finish the function by pressing ctrl‐shift‐enter to execute the function. Just pressing enter is not sufficient.
Upon pressing ctrl‐shift‐enter, two cells are filled. The one on the left is the slope, and the one on the right is the y‐intercept. Formatting the cells to show more decimal places might be necessary to see the number of significant figures that you want.
At this point, just run the values through the equations.
So, the half‐life of the drug is 13.9 h.
Published on May 6, 2014