Please help with python pandas questions $3$a and $3$bQuestion $3$a: Join Tables

Hint: pd$.$merge $($documentation$)$ could be useful here. Note that the order of records in calls and calls$\_$lat$\_$lon are the same.

Question $3$b: Check for Missing Values

It seems like every record has valid GPS coordinates:

$[]$: # just run this cell

# fraction of valid lat$/$lon entries

$($ calls$[["$Lat$",$ "Lon"$]].$isna$()).$mean$()$

However, a closer examination of the data reveals something else. Here's the first few records of our data again:

$[]$: calls.head$(5)$

the same columns of calls.

$[]missin{g}_{l}a{t}_{l}on=$dots

$missin{g}_{l}a{t}_{l}on.$head$()$