The amount of time travellers at an airport spend with customs officers has a mean of 34 seconds and a standard deviation of o = 12 seconds. For a random sample of 50 travellers, what is the probability that their mean time spent with customs officers will be: Standard Normal Distribution Table a. Over 30 seconds? 0.0000 X Round to four decimal places if necessary b. Under 35 seconds? 0.0000 Round to four decimal places if necessary c. Under 30 seconds or over 35 seconds? 0.0000 Round to four decimal places if necessary