Dr. Triboli sampled n = 47 people and asked them how many siblings they have. To determine if the sample has significantly more siblings than the population, Dr. Triboli compared the sample mean to the population, which had a mean of m = 8.4 with a standard deviation of s = 4.3 . If Dr . Tiboli's sample had an average number of siblings of = 6.9 , what z -score does that sample mean to represent? Round your answer to 2 decimal places if appropriate. .