A neuropsychologist is interested only in studying the most deviant portion of this population, that is, those individuals who fall within the top 10% and the bottom 10% of the distribution. She must determine the ages that mark these boundaries. What are these ages?

To determine the ages that mark the boundaries for the top 10% and bottom 10% of the distribution, the neuropsychologist will need a dataset of ages for the population she is studying. With this dataset, she can follow these steps:

1. Sort the ages in ascending order from lowest to highest.
2. Calculate the total number of data points in the dataset.
3. Find the index values that correspond to the top 10% and bottom 10% of the dataset.

To find the age that marks the boundary for the top 10%, the neuropsychologist can follow these steps:

1. Calculate 10% of the total number of data points in the dataset.
2. Round the result to the nearest whole number to determine the number of data points in the top 10%.
3. Find the age value at the index position equal to the rounded number calculated in the previous step.

Similarly, to find the age that marks the boundary for the bottom 10%, the neuropsychologist can follow these steps:

1. Calculate 10% of the total number of data points in the dataset.
2. Round the result to the nearest whole number to determine the number of data points in the bottom 10%.
3. Find the age value at the index position equal to the rounded number calculated in the previous step.

By applying these steps to her dataset, the neuropsychologist will be able to determine the ages that mark the boundaries for the top 10% and bottom 10% of the distribution.