Determine whether or not the equations represent a direct variation. sort the equations into the appropriate category y+3x x+-1 y+ (2/7)x -0.5x=y y = 2.2x=7 y+4

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.