For the cadmium data set, calculate the detection limit.
There is a 1 in 1000 chance that a person in their 40s with no symptoms has a particular type of cancer. The screening test for this form of cancer classifies screened patients correctly 90% of the time. A person in their 40s with no symptoms is screened and the results are positive for the tested cancer. Calculate the probability that this particular person actually has this type of cancer. Clearly show all formulas, logic, and calculations.
The US Department of Defense is in the process of disposing of all VX nerve agent chemical warfare stocks to meet Chemical Disarmament Treaty requirements. Chemical neutralization and incineration are the technologies being used for disposal. Prior to operations, one of the on-site laboratories recently developed and validated standard addition methodology to verify the effectiveness of the neutralization process in destroying VX. Samples from a recent VX neutralization process batch were sent to the chemical plant’s on-site lab for standard addition analysis. The following data were obtained:
|
VX Spike Added (pg/mL ) |
VX Peak Area |
|
0 |
7,989 |
|
5 |
8,952 |
|
10 |
20,885 |
|
15 |
22,318 |
|
20 |
28,068 |
|
30 |
46,734 |
Determine the amount of remaining VX in the chemically neutralized batch, in units of ppb ( picograms / microliter ).
Make a plot of the data and the standard addition curve. Clearly show your work.
State what you think these laboratory results indicate about the effectiveness of the chemical plant’s neutralization process for this batch of VX.