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Erin bought christmas cards for $2 each to send to her family and friends. which variable is the dependent variable?

Write 5(6x+4)-2(5x-2) in the form a(bx+c) where a,b and c integers and a> 1

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.