Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE roller_coaster ( Roller_Coaster_ID int, Name text, Park text, Country_ID int, Length real, Height real, Speed text, Opened text, Status text )
TABLE: CREATE TABLE country ( Country_ID int, Name text, Population int, Area int, Languages text )

### Question ###
Show the names of countries and the average speed of roller coasters from each country. Plot them as bar chart.

### Accurate SQL ###

SELECT T1.Name, AVG(T2.Speed) FROM country AS T1 JOIN roller_coaster AS T2 ON T1.Country_ID = T2.Country_ID GROUP BY T1.Name