In the USA the maximum acceptable level for exposure to microwave radiation is 10 W/cm2 (microwatts per square centimetre). It is feared that a large TV transmitter may have raised the level of ambient microwave radiation above this level. Fourteen widely-spaced monitoring sites were selected among homes at roughly equal distances from the transmitter. For these sites, the mean radiation level was 10.95 W/cm2, with a standard deviation of 1.24 W/cm2.

(a) Do these results indicate that microwave radiation exposure is at an unacceptable level? Conduct an appropriate hypothesis test using = 1%.

(b) If you were a parent with young children and you lived near the transmitter, would you want the significance level of the test to be 1% or 5%? Justify your answer. What significance level would you want if you were the owner of the transmitter?

(c) Provide a 90% confidence interval for the mean microwave radiation at this distance from the transmitter.