Expectation value , significance

A decrease in male fertility to 49% below expected values (significant at p=0.05) was reported in one of four 1,2-dibromoethane manufacturing plants (Wong et al. 1979). After adjustment for workers who had vasectomies and one whose wife had a hysterectomy, the reduction in fertility was 29% and no longer significant at that level. 

Determine whether there is a significant difference between the experimental mean and the expected value at a = 0.01. 

A2.6540-g sample of an iron ore known to contain 53.51% w/w Fe is dissolved in a small portion of concentrated HCl and diluted to volume in a 250-mL volumetric flask. A spectrophotometric method is used to determine the concentration of Fe in this solution, yielding results of 5840, 5770, 5650, and 5660 ppm. Determine whether there is a significant difference between the experimental mean and the expected value at a = 0.05. 

If the molecular species were at m/z 195 (case (b) above) the ion of m/z 163 is generated by a loss of 32 Da. A similar loss from the adduct ion would not be unusual, in this case an ion at m/z (217 — 32), i.e. m/z 185 would be expected. No significant ion of this m/z value is observed and while this is not conclusive it would suggest that this is not the explanation. 

Test Nnmber correct Number incorrect Total % Correct No. correct in excess of expectancy in cr values Significant difference... 

Of the 20 reduced or disulfide bond-free proteins for which the Rg of the chemically or thermally unfolded state has ben reported, 17 fall on a single curve (Fig. 4). Fitting the Rg of these 17 proteins produces a strong, statistically significant correlation (r 2 = 0.96) and an exponent, v = 0.61 d= 0.03, startlingly close to the expected value for an excluded-volume random coil chain. 

One can expect that the electron density corresponding to the electronic state of lowest energy is roughly constant in the interior of the metal and decreases to zero outside the metal. This means that the potential seen by an electron, due to the ion cores and the other electrons, is roughly constant inside the metal, with a value significantly lower than the potential outside. The simplest model for electrons in a metal, the Sommerfeld38 model, takes this potential as -V0 inside and 0 outside. One is then led to consider the one-dimensional Schrodinger equation... 

Because of the way it is calculated, particularly the way the constant factor is ignored, the expected value of DW is two, when the data does in fact meet all the specified criteria random, independent errors, etc. Nonlinearity will cause the computed value of DW to be statistically significantly less than two. (Homework assignment for the reader what characteristic will make DW be statistically significantly greater then two )... 

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