The file Bulbs contains the life (in hours) of a sample of forty 6-watt LED (light emitting diode) light bulbs produced by Manufacturer A and a sample of forty 6-watt LED light bulbs produced by Manufacturer B.

Use the following class interval widths for each distribution: 

Manufacturer A: 46,500 but less than 47,500; 47,500 but less than 48,500; and so on. Manufacturer B: 47,500 but less than 48,500; 48,500 but less than 49,500; and so on.

a. Construct percentage histograms on separate graphs and plot the percentage polygons on one graph.

b. Plot cumulative percentage polygons on one graph.

c. Which manufacturer has bulbs with a longer life—Manufacturer A or Manufacturer B? Explain