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Pull-strength tests on 10 soldered leads for a semiconductor device yield the following results, in pounds of force required to rupture the bond: 19.8, 12.7, 13.2, 16.9, 10.6, 18.8, 11.1, 14.3, 17.0, and 12.5 Another set of 8 leads was tested after encapsulation to determine whether the pull strength had been in- creased by encapsulation of the device, with the following results:24.9, 22.8, 23.6, 22.1, 20.4, 21.6, 21.8, and 22.5 Comment on the evidence available concerning equality of the two population mean. Assume that the data come from normal distribution and their variances are unequal