12.53 Two different machine control-button configurations are being tested. Recognizing that some operators are faster than others, management uses seven operators as blocks, then has each operator carry out a standard operation using each control-button layout. Each operator proceeds from one treatment to the next in a random order, and the times for completion of the operation are shown here. At the 0.05 level, determine whether the treatment effects of the two layouts could be zero. (Use data file XR12053.)

1 Control-Button Configuration 2 6 seconds Operator ABCDE 5 9 6 11 8 13 10 10 F 9 G 12 709 10