The following are the hours of operation to failure of 38 light bulbs.
150 389 345 310 20 310 175 376 334 340 332 331 327 344 328 341 325 2 311 320 256 315 55 345 111 349 245 367 81 327 355 309 375 316 336 278 396 287
Use a suitable statistical computer program to test whether the mean failure time of such light bulbs is significantly less than 300 hours. Use the 0.01 level of significance.