An old adage used when cutting during construction is shown. Does this practice increase precision, accuracy, or both?

Se tiene en una caja de canicas 10, 4 blancas y 6 negras ¿cual es la probabilidad que en 2 extracciones con reemplazo sean blancas? ¿cual es la probalidad que en 2 extracciones sin reemplazo sean negras?

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.

Hi i’m not sure how to do question 20 if u could explain how to do it that’d b great