Two concrete plants are providing concrete to a construction site. While the intended design is the same, five specimens are taken from each plant, with the following results of crushing strength:

Plant 1 : 34700, 36800, 35200, 33900, 35800 kN/m2 Plant 2: 33800, 34700, 35500, 34600, 34000 kN/m2 Can we conclude

(a) that both plants fulfill the design strength of 35000 kN/m2 and

(b) that the strengths of the concrete from the two plants are the same?