19. Light Bulbs A manufacturer of industrial light bulbs wants the bulbs to have a mean length of life that is acceptable to its customers and a variation in length of life that is relatively small. A sample of 20 bulbs tested produced the following lengths of life (in hours):

2100 2302 1951 2067 2415 1883 2101 2146 2278 2019 1924 2183 2077 2392 2286 2501 1946 2161 2253 1827 The manufacturer wishes to control the variability in length of life so that  is less than 150 hours. Do the data provide sufficient evidence to indicate that the manufacturer is achieving this goal? Test using a 5.01.