You were extremely impressed with the eclipse last week, so you've decided to collect some data to learn about how much time people spent traveling to see it. You sampled 20 of your friends, and found that they drove an average of 130 minutes to see the eclipse. Based on past driving studies, you can assume that the population standard deviation for the driving times is 18 minutes. You have been asked to determine a 95% two-sided confidence interval for the eclipse travel times for the general population. What would be z in this? (to 2 decimal places)