If the standard deviation of a normally distributed population is 20.0 and we take a sample of size 4, then the standard error of the mean is

How many lines can be drawn through points j and k? 0 1 2 3

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

2people are trying different phones to see which one has the better talk time. chatlong has an average of 18 hours with a standard deviation of 2 hours and talk-a-lot has an average of 20 hours with a standard deviation of 3. the two people who tested their phones both got 20 hours of use on their phones. for the z-scores i got 1 for the chatlong company and 0 for talk-a-lot. what is the percentile for each z-score?