Which of these is not a measure of variation for a data set?

Scores on the cognitive scale of the bayley-scales of infant and toddler development range from 1 to 19, with a standard deviation of 3. calculate the margin of error in estimating the true mean cognitive scale score, with 99% confidence, if there are 12 infants and toddlers in a sample.

Which graph represents the linear function below? y-3=1/2(x+2)

Which equation can be solved to find x the measure of jk in the apex