Carbon 14 dating not accurate
Whether there's a data point on the Y-axis or not, the Y-intercept of the line doesn't change as the slope of the isochron line does (as shown in Figure 5).
Therefore, the Y-intercept of the isochron line gives the initial global ratio of could be subtracted out of each sample, and it would then be possible to derive a simple age (by the equation introduced in the first section of this document) for each sample.
Now that the mechanics of plotting an isochron have been described, we will discuss the potential problems of the "simple" dating method with respect to isochron methods.
The amount of initial wouldn't change over time -- because it would have no parent atoms to produce daughter atoms.
especially in absence of cross-checks by different methods, or if presented without sufficient information to judge the context in which it was obtained.
Since the data points have the same Y-value and a range of X-values, they initially fall on a horizontal line: half-lives will include zero within its range of uncertainty.
(The range of uncertainty varies, and may be as much as an order of magnitude different from the approximate value above.
(Rocks which include several different minerals are excellent for this.) Each group of measurements is plotted as a data point on a graph.
The X-axis of the graph is the ratio of in a closed system over time.