Exercise 18: [similar] The powdered chlorine added to swimming pools to combat algae has a relatively short shelf life before it loses its effectiveness. Records indicate that the mean shelf life of a 5-gallon jug of chlorine is 2,000 hours. A new ingredient, Cobalt, was added to the chlorine to increase the shelf life. A sample of twenty jugs of chlorine was tested & the mean was 2050 hours with a population std dev of 100 At the .02 level of significance, has the Cobalt increased the shelf life of the chlorine? Ho: 1950 1950 Z= Z = Ho is Conclusion