02-starting-with-data.md: Typos - end sentences with question marks or periods (#442)

Author: maneesha

_episodes/02-starting-with-data.md

@@ -484,13 +484,13 @@ summary stats.
 
 > ## Challenge - Summary Data
 >
-> 1. How many recorded individuals are female `F` and how many male `M`
+> 1. How many recorded individuals are female `F` and how many male `M`?
 > 2. What happens when you group by two columns using the following syntax and
->    then grab mean values:
+>    then grab mean values?
 >   - `grouped_data2 = surveys_df.groupby(['plot_id','sex'])`
 >   - `grouped_data2.mean()`
 > 3. Summarize weight values for each site in your data. HINT: you can use the
->   following syntax to only create summary statistics for one column in your data
+>   following syntax to only create summary statistics for one column in your data.
 >   `by_site['weight'].describe()`
 >
 >