Tim is measuring the concentrations of neurotransmitters produced by rat brains when fed with an alkaloid stimulant. His replicate results yielded the following concentrations (in μM): 116.0, 97.9, 114.2, 106.8 and 103.3. For four degrees of freedom, student’s t at 90% CI is 2.132.

1. a) 10 pt. His standard control solution is guaranteed to yield 116.2 μM under the same conditions. Are his results accurate at 90% confidence level?

2. b) 5 pt. If instead Tim had to report this with a 99% confidence level, would the new CI likely include the standard control concentration? Discuss why or why not.

3. c) 10 pt. Tim obtained a new standard that is nominally 15.2 μM. Based on the limits allowed by the precision of his method, could he claim to measure this concentration? Prove using calculations.

4. d) 5 pt. Discuss briefly what a false negative and a false positive are using two Gaussian curves, one centered in the blank and another centered on the LOD. Assume equal s for both curves