• incanter

# sample-multinomial-params

## incanter.bayes

• (sample-multinomial-params size counts)
Returns a sample of multinomial proportion parameters.
The counts are assumed to have a multinomial distribution.
A uniform prior distribution is assigned to the multinomial vector
theta, then the posterior distribution of theta is
proportional to a dirichlet distribution with parameters
(plus counts 1).

Examples:
(use '(incanter core stats bayes charts))

(def samp-props (sample-multinomial-params 1000 [727 583 137]))

;; view means, 95% CI, and histograms of the proportion parameters
(mean (sel samp-props :cols 0))
(quantile (sel samp-props :cols 0) :probs [0.0275 0.975])
(view (histogram (sel samp-props :cols 0)))
(mean (sel samp-props :cols 1))
(quantile (sel samp-props :cols 1) :probs [0.0275 0.975])
(view (histogram (sel samp-props :cols 1)))
(mean (sel samp-props :cols 2))
(quantile (sel samp-props :cols 2) :probs [0.0275 0.975])
(view (histogram (sel samp-props :cols 2)))

;; view a histogram of the difference in proportions between the first
;; two candidates
(view (histogram (minus (sel samp-props :cols 0) (sel samp-props :cols 1))))

### Source incanter/bayes.clj:99 top

```(defn sample-multinomial-params
" Returns a sample of multinomial proportion parameters.
The counts are assumed to have a multinomial distribution.
A uniform prior distribution is assigned to the multinomial vector
theta, then the posterior distribution of theta is
proportional to a dirichlet distribution with parameters
(plus counts 1).

Examples:
(use '(incanter core stats bayes charts))

(def  samp-props (sample-multinomial-params 1000 [727 583 137]))

;; view means, 95% CI, and histograms of the proportion parameters
(mean (sel samp-props :cols 0))
(quantile (sel samp-props :cols 0) :probs [0.0275 0.975])
(view (histogram (sel samp-props :cols 0)))
(mean (sel samp-props :cols 1))
(quantile (sel samp-props :cols 1) :probs [0.0275 0.975])
(view (histogram (sel samp-props :cols 1)))
(mean (sel samp-props :cols 2))
(quantile (sel samp-props :cols 2) :probs [0.0275 0.975])
(view (histogram (sel samp-props :cols 2)))

;; view  a histogram of the difference in proportions between the first
;; two candidates
(view (histogram (minus (sel samp-props :cols 0) (sel samp-props :cols 1))))

"
([^Integer size counts]
(sample-dirichlet size (plus counts 1))))```
Vars in incanter.bayes/sample-multinomial-params: defn
Used in 0 other vars