Fit both logistic and probit models modelling proportion

Reference no: EM13641851

The following data show the number of fruit fly killed at varying concentrations of nicotine.

The number of ies killed in n exposures can be assumed to follow a binomial distribution

(from Hand et al [2]).

(a) Fit both logistic and probit models, modelling proportion killed as a function of nicotine concentration. Are there any obvious differences in the fit of these models?

(b) Plot the observed proportions killed and the two fitted models on the same plot.

Comment on the fit of the models and any differences between models.

(c) Using the models in (a), estimate the nicotine concentration that would kill 50% of flies. Also estimate the dose hat would kill 90% of flies.

(d) Often the experimental factor X is replaced by ln(X) in these quantal assay experiments. Repeat (a) using ln(X) and comment on the fit of these models.

(e) What issues need to be considered when deciding which single model is 'best' between the four models (i.e. the two in (a) and two in (c))? Are any of the four models obviously superior in this example?

Nicotine concentration	Flies	Number	Percent
(g/100cc)	exposed	killed	killed
0.1	47	8	17
0.15	53	14	26.4
0.2	55	24	43.6
0.3	52	32	61.5
0.5	46	38	82.6
0.7	54	50	92.6
0.95	52	50	96.2

Reference no: EM13641851

Questions Cloud

Morphine pkb 580 is the active ingredient in opium it is : morphine pkb 5.80 is the active ingredient in opium. it is used as an analgesic that directly acts on the central

A uniform electric field of 8 vm exists between the plates : a uniform electric field of 8 vm exists between the plates of a parallel plate capacitor. how much work is required to

An important part of the customer service responsibilities : an important part of the customer service responsibilities of a cable company relates to the speed with which trouble

In a pacemaker used by a heart patient a capacitor with a : in a pacemaker used by a heart patient a capacitor with a capacitance of 29-microf is charged to 2.0 v and then

Fit both logistic and probit models modelling proportion : the following data show the number of fruit fly killed at varying concentrations of nicotine.the number of ies killed

After flying for 15 min in a wind blowing 42 kmh at an : after flying for 15 min in a wind blowing 42 kmh at an angle of 34deg south of east an airplane pilot is over a town

What is the reaction when elemental magnesium and elemental : what is the reaction when elemental magnesium and elemental copper are placed in an aqueous solution of copper sulfate?

Assuming that the particles velocity is perpendicular to : the solar wind is a thin hot gas given off by the sun. charged particles in this gas enter the magnetic field of the

A mixture of barium and silver is to be analyzed the barium : a mixture of barium and silver is to be analyzed. the barium component reacts with acid to generate hydrogen gas while

User Account

All Pages