Constructing a grouped frequency distribution and a histogram
Sort raw values into classes, then build the histogram bar by bar. The class width is given; the work is deciding which class each value falls in without dropping any.
A short walkthrough explaining what you need to know and how to solve this question type lands here once it's recorded.
ALEKS randomizes the numbers each attempt, but the question shape stays the same. Here are three example versions you might see.
Same eighteen values: 20, 11, 6, 8, 3, 16, 10, 7, 15, 11, 11, 2, 5, 4, 8, 13, 9, 12.
How many fall in the class 14 to 19?
A distribution uses the classes 10 to 19, 20 to 29, 30 to 39.
What is the class width?
Classes are 2 to 7 and 8 to 13. A cyclist rode exactly 8 miles.
Which class does that value belong to? Type the lower bound of the class.
Eighteen cyclists reported the miles they biked last week:
20 11 6 8 3 16
10 7 15 11 11 2
5 4 8 13 9 12
Complete the grouped frequency distribution using a class width of 6.
The first class
The busiest class
Now build it
What the picture bought you
The shape is the point. Most cyclists rode between 8 and 13 miles, and the tail to the right is thin — information the raw list of eighteen numbers does not give up at a glance.
The cost is that the individual values are now gone. Those nine cyclists in the 8 to 13 class could be any mix of numbers in that range, and nothing in the histogram will tell you which. That trade is worth remembering, because it is exactly why the next question — estimating a mean from a distribution — can only ever be an estimate.