clarify text from the adjusting for delays section

episodes/delays-functions.Rmd

@@ -388,25 +388,22 @@ Using the serial interval instead of the generation time is an alternative that
 
 Estimating $R_t$ requires data on the daily number of new infections. Due to lags in the development of detectable viral loads, symptom onset, seeking care, and reporting, these numbers are not readily available. All observations reflect transmission events from some time in the past. In other words, if $d$ is the delay from infection to observation, then observations at time $t$ inform $R_{t−d}$, not $R_t$. [(Gostic et al., 2020)](https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1008409#sec007)
 
-![Timeline for chain of disease reporting, the Netherlands. Lab, laboratory; PHA, public health authority. From [Marinović et al., 2015](https://wwwnc.cdc.gov/eid/article/21/2/13-0504_article)](fig/disease-reporting.jpg)
+![**Timeline for chain of disease reporting, the Netherlands.** Lab, laboratory; PHA, public health authority. From [Marinović et al., 2015](https://wwwnc.cdc.gov/eid/article/21/2/13-0504_article)](fig/disease-reporting.jpg)
 
-The **delay distribution** could be inferred jointly with the underlying times of infection or estimated as the sum of the **[incubation period](../learners/reference.md#incubation)** distribution and the distribution of delays from symptom onset to observation from line list data **([reporting delay](../learners/reference.md#reportingdelay))**.
+The **delay distribution** could be inferred jointly with the underlying times of infection or estimated as the sum of the [incubation period](../learners/reference.md#incubation) distribution and the distribution of delays from symptom onset to observation from line list data ([reporting delay](../learners/reference.md#reportingdelay)). For `{EpiNow2}`, we can specify these two complementary delay distributions in the `delays` argument.
 
-For `{EpiNow2}`, we can specify these two complementary delay distributions in the `delays` argument.
-
-![$R_{t}$ is a measure of transmission at time $t$. Observations after time $t$ must be adjusted. ICU, intensive care unit. From  [Gostic et al., 2020](https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1008409#sec007)](fig/rt-adjusting-delays.png)
+![**$R_{t}$ is a measure of transmission at time $t$.** Observations after time $t$ must be adjusted. ICU, intensive care unit. From  [Gostic et al., 2020](https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1008409#sec007)](fig/rt-adjusting-delays.png)
 
 ::::::::::::::::::::::::::::::::: challenge
 
-### Reuse an Incubation period for COVID-19
-
-Use `{epiparameter}` to:
+### Use an Incubation period for COVID-19 to estimate Rt
 
-- Find an incubation period for COVID-19.
-- Add our last `epinow()` code chunk using the `delays` argument and the `delay_opts()` helper function.
+Estimate the time-varying reproduction number for the first 60 days of the `example_confirmed` data set from `{EpiNow2}`. Access to an incubation period for COVID-19 from `{epiparameter}` to use it as a reporting delay.
 
 ::::::::::::::::: hint
 
+Use the last `epinow()` calculation using the `delays` argument and the `delay_opts()` helper function.
+
 The `delays` argument and the `delay_opts()` helper function are analogous to the `generation_time` argument and the `generation_time_opts()` helper function.
 
 ```r