Prob-5 In a certain design, it is important that standard deviation of the current be less than 18 mA. In a test of n=16 parts, the sample standard deviation is found to be 15 mA. Can we be 95% confident that the standard deviation will not exceed 18 mA? {Solution Tips: Yes; if upper bound of 95% confidence interval of std. not greater than 18 mA} Solution: Prob-6 A Fabric is unsuitable for dyeing if its water pickup is less than 55%. Data set of % pickup values has n=25, and sample mean = 56.80%, and sample std. s = 4.54%. Can we 95% confident that µ<55% and cotton fabric is unsuitable for dyeing? {Solution Tips: Use one-sided confidence interval. Yes; if lower bound of one-sided 95% confidence interval less than 55 %.} Solution: Prob-7 A simple spring is used to measure force. The spring is considered to be linear, so that F=kx, where F is the force in newton, k is the spring constant in Newton per centimeter, and x is the displacement in cm. If x=20.0 ±1.25 cm and k=800 ±16 N/cm, compute the uncertainty of the measured force in absolute (dimensional) and relative (%) terms. Solution: