Answer:
Definitions:
The third quartile, denoted by Q3 , is the median of the upper half of the data set. This means that about 75% of the numbers in the data set lie below Q3 and about 25% lie above Q3;
The upper half of a data set is the set of all values that are to the right of the median value when the data has been put into increasing order;
First, we verify data in increasing order:
21, 24, 25, 28, 29, 35, 37, 38, 42 ( okay);
The median is 29;
Therefore, the upper half of the data is {35, 37, 39, 42};
Q3 = ( 37 + 39 ) / 2 = 76 / 2 = 38;
Step-by-step explanation:
