A & P Lab Review Chapter 8

What is the difference between a frequency polygon and an​ ogive?

A frequency polygon displays class frequencies while an ogive displays cumulative frequencies. - These two graphs display the data​ differently, so it is useful to graph both when trying to find patterns in a data set.

What is an advantage of using a​ stem-and-leaf plot instead of a​ histogram? What is a​ disadvantage? What is a disadvantage of using a​ stem-and-leaf plot instead of a​ histogram?

Histograms easily organize data of all sizes where​ stem-and-leaf plots do not.

Determine whether the statement is true or false. If it is​ false, rewrite it as a true statement. The midpoint of a class is the sum of its lower and upper limits divided by two.

The statement is true. - The statement is​ true, as shown by the formula below. Midpoint equals = (Lower class limit) + (Upper class limit) / 2

Determine whether the statement is true or false. If it is​ false, rewrite it as a true statement. When each data class has the same​ frequency, the distribution is symmetric.

True - A frequency distribution is symmetric when a vertical line can be drawn through the middle of the graph of the distribution and the resulting halves are approximately mirror images. When each data class has the same​ frequency, the distribution is uniform. A uniform distribution is also symmetric.

Determine whether the statement is true or false. If it is​ false, rewrite it as a true statement. Class boundaries ensure that consecutive bars of a histogram touch.

True - Because consecutive bars of a histogram must​ touch, bars must begin and end at class boundaries instead of class limits. Class boundaries are the numbers that separate classes without forming gaps between them.

What is an advantage of using a​ stem-and-leaf plot instead of a​ histogram? What is a​ disadvantage? What is an advantage of using a​ stem-and-leaf plot instead of a​ histogram?

​Stem-and-leaf plots contain original data values where histograms do not. - In a​ stem-and-leaf plot, each number is separated into a​ stem, such as the​ entry's leftmost​ digits, and a​ leaf, such as the rightmost digit. There should be as many leaves as there are entries in the original data set and the leaves should be single digits. A​ stem-and-leaf plot is similar to a histogram but has the advantage that the graph still contains the original data. Another advantage of a​ stem-and-leaf plot is that it provides an easy way to sort data.

Why should the number of classes in a frequency distribution be between 5 and​ 20?

If the number of classes in a frequency distribution is not between 5 and​ 20, it may be difficult to detect any patterns. - A frequency distribution is a table that shows classes or intervals of data entries with a count of the number of entries in each class. When constructing a frequency distribution from a data​ set, the first step is to decide on the number of classes to include in the frequency distribution. The number of classes should be between 5 and​ 20; otherwise, it may be difficult to detect any patterns.

Determine whether the statement is true or false. If it is​ false, rewrite it as a true statement. Some quantitative data sets do not have medians.

The statement is false. All quantitative data set have medians. - The median of a data set is the value that lies in the middle of the data when the data is ordered. If the data has an odd number of​ entries, the median is the middle data entry. If the data has an even number of​ entries, the median is the mean of the two middle data entries. All quantitative data sets have medians.