Dear Sir, Thank you for sharing your knwolodge!!!! ;) I don´t understand two things: 1) In 4min 27, when you calculate Corr,P you aply =ln (F5/(1-E5). Why E5? Isn´t ln(F5/(1-F5)? 2) Why did you use "five" (5) plus in Probit in the calculation? When I use logit and when I use Probit? Very very thanks!
@slademeister8 жыл бұрын
+Thelma P. we add 5 so that the probit is in the middle with no zero values since you can't plot a zero on a log scale. e.g. No zero dose.
@shivabhattarai17238 жыл бұрын
+Slade Matthews Can we add numbers other than 5.
@slademeister8 жыл бұрын
+Shiva Bhattarai We could if we wanted to shift the centre of the distribution. But this is not a standard use of probit.
@jeffreygood88498 жыл бұрын
Excellent video! Any advice for calculating 95% confidence intervals for the LC50 values obtained by this method?
@kamakshaiah7 жыл бұрын
thanks for the video. very much useful. However, is it appropriate to predict for test value 5 for probit. I think probit is a special case of dichotomous dependent variable, where the responses must either 0 or 1 or 1, 2. Is it not?
@ghulamalibaloch52417 жыл бұрын
sir how we can draw this graph.. please explain .. thanks
@slademeister8 жыл бұрын
I note that in calculating the logit you put the corrected probability of death over one minus the uncorrected P. Was this intentional? I feel that the odds should add up to one (outside of horse racing!! ). PS. An excellent video very clear indeed.
@serviosilver94407 жыл бұрын
Slade Matthews because it is approximately 4 times OLS
@lizflorezp8 жыл бұрын
this video safe my life
@alamreweyayu49776 жыл бұрын
an excellent video! I learnt a lot from your video and thanks.
@naveedkhan-pv4wc8 жыл бұрын
how the graph was formed
@DaisyAleksa9 жыл бұрын
why we need to add 5 at probit?
@outdoors01457 жыл бұрын
This was done by Finney 1971 I believe and was due to the inverse normal distribution resulting in negative numbers below 0.5. Good video, additionally GLM can be used in R to do all this.
@KashirVoice6 жыл бұрын
how the graph is draw in this videoif any one knows please tell