Between 201 1 and 2012, there were 5 comets that passed close enough to Earth and were properly positioned to be visible. These comets and their distance of closest approach are listed in the table below. Comet Distance of Closest Approach (au) (308635) 2005 YUs5 0.002172 2011 XC2 0.0023 2012 LZ1 0.036415 (214869) 2007 PA: 0.043294 4179 Toutalis 0.046332 a) Based on this sample, find i) the mean, mean deviation, and standard deviation of the distance of closest approach; State your answers correct to 6 decimal places. ii) find the z-score of 2012 LZi's distance of closest approach. State your answer correct to 6 decimal places. b) If a comet collides with earth then its distance of closest approach must be zero. Based on this sample, how many standard deviations below the mean is a distance of closest approach equal to zero? State your answer correct to 6 decimal places