The viscosity of a specific liquid polymer, VVV, is known to be normally distributed with a mean of 1420 mPa·s and a standard deviation of 115 mPa·s. A quality control engineer takes a random sample of 24 independent batches to monitor the stability of the production line. Determine the probability that the mean viscosity of this sample, Vˉ\bar{V}Vˉ, is less than 1385 mPa·s.
324 exam-style questions on WJEC A Level Maths 4.2 Statistical distributions (A-level only), covering 4.2.1 Statistical distributions (A-level only), 4.2.2 Statistical distributions (A-level only), and 4.2.3 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.