Question

A candle manufacturer wants to state an average burning time on the packaging of his perfumed candles. He records the burning times for a random sample of 15 candles and enters the data into a computer package, which tells him that a 90% confidence interval for the mean burning time is from 48.388 hours to 56.012 hours. What are the mean burning time and its standard error for the sample of 15 candles?

The manufacturer wants to compare the burning times of his identically sized perfumed and unperfumed candles. In particular, he suspects that the oils used in his perfumed candles may result in their burning more quickly on average. He lights a random sample of 19 unperfumed candles and finds that their mean burning time is 58.4 hours and the standard deviation of their burning times is 10.2 hours. Perform a test at the 5% significance level to investigate his suspicions about the mean burning times, stating your hypotheses and conclusions clearly

Answer 1