Hello, I have a table that collects a rating, every 15 minutes

mhour	mmin	mRating
1	        0015	1.76
1	        0030	1.72
1	        0045	1.66
1	        0100	1.64
2	        0115	        1.64
2	        0130	1.62
2	        0145	1.7

And I would like to use SQL to generate an average of the mRatings, for each hour.

mhour	AvgRating
1	        1.695
2	        1.653       

Is this possible?
Thank you,
Steve