Rachel's science class places weights on a scale during an experiment. each weight weighs 8.1 kilograms. if the class puts 9 weights on the scale at the same time, what will the scale read?

Extra points! find the missing dimension! need asap

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.

What is the period of the sinusoidal function ?