The stem and leaf plot should then look like this: Table 5. One type of graph that displays these features of the data is called a stem-and-leaf plot or stemplot. Step 5: Include an explanation. Here we can see that the median is 28 years old. So if needed, you can just take a look to get an idea of the spread of the data or you can use the values to calculate the mean, median or mode. Stem and leaf plots are similar to horizontal bar graph, but the actual numbers are used instead of bars.
A distribution is said to be skewed to the right, or positively skewed, when most of the data are concentrated on the left of the distribution. Anything that has a decimal point is rounded to the nearest whole number. . In this example, the tens digits are stems, and the one digits form the leaves. Presidential Ages at Inauguration President Age President Age President Age Washington 57 Lincoln 52 Hoover 54 J. Each proportion on a pie chart represents the proportion of the corresponding class in the data set.
The stems are listed to the left of the vertical line. Britney is a swimmer training for a competition. When looking at a data set, each observation may be considered as consisting of two parts—a stem and a leaf. Where observations are accurate to one or more decimal places, such as 23. However, it is also helpful to have an understanding of the of data sets in general, so be sure to review these concepts prior to beginning work with stem and leaf plots. This is because, except when using box plots explained in the section on , there is no strict rule on how far removed a value must be from the rest of a data set to qualify as an outlier. A stem and leaf plot can quickly be turned into a histogram as well to show the data using bars.
Check out the example showing ages at a birthday party. Each morning, a teacher quizzed his class with 20 geography questions. It is difficult to know from the plot whether Elliot has improved or not because we do not know the order of those scores. The stem and leaf plot should look like this: Table 2. The ordered stem and leaf plot is shown below: Table 6. Harrison 55 Ford 61 W.
It is an observation value that is significantly different from the rest of the data. The leaf consists of a final significant digit. They are also useful for highlighting and finding the. Construct a bar graph and a pie chart using this data. If the leaves become too crowded, then it might be useful to split each stem into two or more components. Also, there is no need to separate the leaves digits with punctuation marks commas or periods since each leaf is always a single digit. Roosevelt 51 Jefferson 57 Grant 46 Truman 60 Madison 57 Hayes 54 Eisenhower 62 Monroe 58 Garfield 49 Kennedy 43 J.
By ignoring these two outliers, the previous example's stem and leaf plot could be redrawn as below: Table 9. Use the marks from something like all of your exam results last year or the points your sports team accumulated this season. A stem and leaf plot looks something like a bar graph. The leaf of the number will always be a single digit. See the section on for details on this type of graph. Every day, Elliot recorded his quiz marks on a stem and leaf plot.
A teacher asked 10 of her students how many books they had read in the last 12 months. What is his most common score on the geography quizzes? The table shows the three age groups, the number of people in the town from each age group, and the proportion % of people in each age group. They evolved from 's work in the early 1900s, and are useful tools in. Make a brief comment on what it shows. The last team finished with 3 minutes and 32. Examples of unimodal, bimodal and multimodal line graphs are shown below: General shape The second main feature of a distribution is the extent to which it is symmetric.
Maximum The largest value in a sample data set. Adams 57 Arthur 51 L. Part 2: Creating a Stem and Leaf Plot Here is a set of data on showing the test scores on the last science quiz. The large number of students who obtained high results could mean that the test was too easy, that most students knew the material well, or a combination of both. Here is the sorted set of data values that will be used in the following example: 44, 46, 47, 49, 63, 64, 66, 68, 68, 72, 72, 75, 76, 81, 84, 88, 106 Next, it must be determined what the stems will represent and what the leaves will represent. Try It The following data show the distances in miles from the homes of off-campus statistics students to the college. Stem-and-leaf Graphs One simple graph, the stem-and-leaf graph or stemplot, comes from the field of exploratory data analysis.