Representative fit of force versus extension data and the deduced .

<p>(a) Experimental uncorrected results (blue triangles) showing the variation of persistence length, , as a function of contour length, , shows a pronounced and statistically significant decrease for shorter DNA constructs. Following the correction procedure in the text a corrected is obtained (red squares). Errors shown are standard error of the mean with in ascending contour length. Dashed red line is , blue line is a guide to the eye. (b) Experimental force-extension curve with a WLC model fit (red line) for a 12 kb DNA molecule. For this case and . Inset) The same data on a log scale. (c) Diagram that illustrates the effect that a mismeasurement in microsphere position has upon DNA extension for positive and negative skew. The red arrows start at the extension measured using the arithmetic mean, , and end at the position expected if the skew normal distribution location position, , is used instead.