Use shape and rate to specify uncertain Gamma parameters

vignettes/estimate_infections_workflow.Rmd.orig

@@ -90,10 +90,10 @@ plot(fixed_gamma)
 ```
 
 If distributions are variable, the values with uncertainty are treated as [prior probability densities](https://en.wikipedia.org/wiki/Prior_probability) in the Bayesian inference framework used by _EpiNow2_, i.e. they are estimated as part of the inference.
-For example, to define a variable gamma distribution where uncertainty in the mean is given by a normal distribution with mean 3 and sd 2, and uncertainty in the standard deviation is given by a normal distribution with mean 1 and sd 0.1, with a maximum value 10, you would write
+For example, to define a variable gamma distribution where uncertainty in the shape is given by a normal distribution with mean 3 and sd 2, and uncertainty in the rate is given by a normal distribution with mean 1 and sd 0.1, with a maximum value 10, you would write
 
 ```{r}
-uncertain_gamma <- Gamma(mean = 3, sd = 0.1, max = 10)
+uncertain_gamma <- Gamma(shape = Normal(3, 2), rate = Normal(1, 0.1), max = 10)
 uncertain_gamma
 ```