A survey collected data from families in three groups. Group 1 had 30 families, with a mean of 3.2 children. Group 2 had 12 families, with a mean of 4.5 children. Group 3 had 14 families, with a mean of 2.5 children. What is the overall mean for the survey? In a sample, Z(X-1) = 15 and 2X = 30. What is the mean? 0 We don't have enough information to know. Laurel is studying how much time her classmates spend on social media. She asked 9 random students in her class to keep track of how many hours they spend per week on social media. Calculate the standard deviation of Laurel's sample: Q ~3.75 Q ~3.33 Q ~1.82 Q ~1.93