A convenience store sells two brands of orange juice. Brand A contains 8 fluid ounces and costs $1.28. Brand B contains 12 fluid ounces and costs $1.68. What is the difference in costs, in dollars, per fluid ounce between the two brands of juice?

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.