Get various probabilities associated with each option on 4th downs (go for it, kick field goal, punt).

`add_4th_probs(df)`

- df
A data frame of decisions to be computed for.

Original data frame Data frame plus the following columns added:

- go_boost
Gain (or loss) in win prob associated with choosing to go for it (percentage points).

- first_down_prob
Probability of earning a first down if going for it on 4th down.

- wp_fail
Win probability in the event of a failed 4th down attempt.

- wp_succeed
Win probability in the event of a successful 4th down attempt.

- go_wp
Average win probability when going for it on 4th down.

- fg_make_prob
Probability of making field goal.

- miss_fg_wp
Win probability in the event of a missed field goal.

- make_fg_wp
Win probability in the event of a made field goal.

- fg_wp
Average win probability when attempting field goal.

- punt_wp
Average win probability when punting.

```
# \donttest{
play <-
tibble::tibble(
# things to help find the right game (use "reg" or "post")
home_team = "GB",
away_team = "TB",
posteam = "GB",
type = "post",
season = 2020,
# information about the situation
qtr = 4,
quarter_seconds_remaining = 129,
ydstogo = 8,
yardline_100 = 8,
score_differential = -8,
home_opening_kickoff = 0,
posteam_timeouts_remaining = 3,
defteam_timeouts_remaining = 3
)
probs <- nfl4th::add_4th_probs(play)
#> Computing probabilities for 1 plays. . .
dplyr::glimpse(probs)
#> Rows: 1
#> Columns: 23
#> $ home_team <chr> "GB"
#> $ away_team <chr> "TB"
#> $ posteam <chr> "GB"
#> $ type <chr> "post"
#> $ season <dbl> 2020
#> $ qtr <dbl> 4
#> $ quarter_seconds_remaining <dbl> 129
#> $ ydstogo <dbl> 8
#> $ yardline_100 <dbl> 8
#> $ score_differential <dbl> -8
#> $ home_opening_kickoff <dbl> 0
#> $ posteam_timeouts_remaining <dbl> 3
#> $ defteam_timeouts_remaining <dbl> 3
#> $ go_boost <dbl> 3.688319
#> $ first_down_prob <dbl> 0.3269784
#> $ wp_fail <dbl> 0.03575731
#> $ wp_succeed <dbl> 0.3446303
#> $ go_wp <dbl> 0.1367521
#> $ fg_make_prob <dbl> 0.9752029
#> $ miss_fg_wp <dbl> 0.03068082
#> $ make_fg_wp <dbl> 0.1016282
#> $ fg_wp <dbl> 0.09986893
#> $ punt_wp <dbl> NA
# }
```