The Bureau ofJustice Statistics reports on average a prison sentence for drug offense has a length of 4? months. After an extended campaign to discourage such offenders by increasing the penalty for such crimes a sample of 50 offenders was taken to see if anything changed. The 50 samples were found to have a mean prison stay of 49 months with a standard deviation of 2.8 months. Has there been a signicant increase in the length ofstay injail? Assume alpha = 0.05 Select one: 0 a. There is insufficient evidence at the specied alpha that the mean length oftime exceeds the standard. 0 b. The mean length of time exceeds the standard by alpha. 0 c. The mean length of time is exactly equivalent to the standard. 0 d. There i_sstati5tical evidence at the specied alpha that the mean length oftime exceeds the standard