The Number of Words in the Active Vocabulary of Children

question 63

Essay

The number of words in the active vocabulary of children of a particular age is normally distributed with a mean of 3000 and a standard deviation of 500.
a.Using the normal curve approximation rules,how many words would a child of this age have to know to be in the top 2%,the top 16%,and the top 98%?
b.Illustrate your answer with a sketch.
c.Explain your answers to a person who is familiar with mean,standard deviation,and Z scores,but not with normal curve percentages.

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Definitions:

HLOOKUP

A function in spreadsheet software that searches for a value in the top row of a table or range and returns a value in the same column from a specified row.

INDEX

A function in programming and spreadsheet software that returns the value of an element in a table or array, identified by row and column numbers.

Cells Group

A grouping of cells in applications like Excel, often to perform bulk operations or formatting.

Add Row to End

The action of inserting an additional row at the bottom of a table or list in software applications or documents.