Question

The Precision Scientific Instrument Company manufactures thermometers that are supposed to give readings of 0 C at the freezing point of water. Tests on a large sample of these thermometers reveal that at the freezing point of water, some give readings below 0 C (denoted by negative numbers) and some give readings above 0 C (denoted by positive numbers). Assume that the mean reading is 0 C and the standard deviation of the readings is 0.08 C. Also assume that the frequency distribution of errors closely resembles the normal distribution. A quality assurance engineer collects a sample of 15 thermometers. What is the probability the mean of this sample will be within 0.005 C of the true mean of 0 C?

Answer 1