Code:
SELECT Sum([Machine Data].[Earned Hours]) AS [SumOfEarned Hours], Sum([Machine Data].[Total Time Hours]) AS [SumOfTotal Time Hours], Sum([earned hours]/[total time hours]) AS Total
FROM [Machine Data]
WHERE ((([Machine Data].Date) Between [Forms]![frmDateSpec]![Starting Date] And [Forms]![frmDateSpec]![End Date]));
This query will produce one summed row for all the rows in Machine Data whose dates fall between the Starting Date and End Date. Those two dates, entered by a user, are taken from a form I called frmDateSpec. Don't know where yours come from, but the example works.