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sampling methods

SAMPLING TECHNIQUES INTRODUCTION[Cochran, p18] [Trochim] With probability sampling, a measure of sampling variation can be obtained objectively from the sample itself. Nonprobability sampling or judgm ...

en10216 2 tube

Seamless alloy boiler tube EN10216-2,vitten Seamless EN10216-2 Seamless Steel Tubes for Pressure Purposes. Application:This type tube is widely used for boiler,superheater, shell & tube bundle hea ...