In a study designed to test whether its electric light bulbs are superior to those of a competitor, a manufacturer tested the burning life of 36 of its own randomly selected light bulbs which had an average of x = 630 hours of continuous use with standard deviation s = 24 hours. Another sample of 49 randomly selected bulbs produced by the competitor had an average of x = 605 hours with standard deviation s = 28 hours. Use the = 0.01 level of significance to test the null hypothesis that the corresponding population means are equal against the alternative hypothesis that they are not equal.