Answer:
48 1/2
Step-by-step explanation:
First, find the median of this data. Arrange the data in ascending order:
42, 46, 51, 53, 66, 70, 70, 90. The median is the mean of the two middle terms: median = (53 + 66)/2.
On the left of this median are the lower half of the data: 42, 46, 51 and 53.
The first quartile is the median of this subset.
Take the two middle terms and average them:
(46 + 51)/2 = 97/2, or 48 1/2. This is Q1.
