# Question

The Mental Development Index (MDI) of the Bayley Scales of Infant Development is a standardized measure used in observing infants over time. It is approximately normal with a mean of 100 and a standard deviation of 16.

a. What proportion of children has an MDI of

(i) At least 120?

(ii) At least 80?

b. Find the MDI score that is the 99th percentile.

c. Find the MDI score such that only 1% of the population has MDI below it.

a. What proportion of children has an MDI of

(i) At least 120?

(ii) At least 80?

b. Find the MDI score that is the 99th percentile.

c. Find the MDI score such that only 1% of the population has MDI below it.

## Answer to relevant Questions

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