An index that is a standardized measure used in observing infants over time is approximately normal with a mean of 96 and a standard deviation of 10. a) Using the empirical rule, approximately what percent of infants have an index score between 86 and 126?
b) Using the appropriate table, what proportion of infants have an index score of between 90 and 100?
c) What index score is greater than 33% of the population index scores?
d) What index score is the 89th percentile?