Receptor cells in the retina responsible for color vision and sharp vision are

Which of the following is likely to be most adept at hearing the difference between very similar speech sounds that are not distinguished in their native language?

a. a young infant c. an adolescent b. an older child d. an adult

In order to predict how much an individual's score might change on a

retest, we can use the a. standard error of measurement b. standard error of the mean c. standard error of estimate d. point biserial correlation