The circle graph below shows the mode of transportation for students at a local middle school. Transportation to School Bus 30% Walk 45% Bicycle 20% Car 5% If 900 students attend the school, how many more ride the bus to school than ride in a car to school?

25

270

225

45 ​

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.