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Unit 11(Evaluating Descriptive Data)questions with answers
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Unit 11(Evaluating Descriptive Data)questions with answers
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Unit 11(Evaluating DescriptiveData)questions with answers
Purpose of DESCRIPTIVE STATISTICS - correct answer ✔✔The goal of descriptive statistics is to describe,
summarize, or make sense of numerical data.
Researchers use graphic representations such as bar graphs, line graphs, and scatter plots as well as
measures of central tendency (i.e., mode, median, and mean) to display and analyze this data. Before
this analysis can start, a researcher must have data set to interpret. The researcher can summarize the
variables in a data set one at a time, as well as examine how the variables are interrelated (e.g., by
examining correlations). The key question in descriptive statistics is how researchers should
communicate the essential characteristics of the data.
statistics - correct answer ✔✔a branch of mathematics that deals with the analysis of numerical data. It
can be divided into two broad categories called descriptive statistics and inferential statistics.
Inferential statistics was discussed previously in Unit 3, Module 3 in regards to Quantitative research.
In descriptive statistics, however, the goal is to describe, summarize, or make sense of a particular set of
data. The focus is more on interpretation than on calculation.
inferential analysis - correct answer ✔✔Uses the laws of probability to make suggestions about
populations based on sample data
descriptive analysis - correct answer ✔✔Goal is to summarize and explain a set of data
qualitative analysis - correct answer ✔✔Focused on the analysis of nonnumerical data, such as words
and pictures
Descriptive statistics starts with a data set - correct answer ✔✔the researcher attempts to convey the
essential characteristics of the data by arranging it into a more interpretable form (e.g., by forming
frequency distributions and generating graphical displays) and by calculating numerical indexes, such as
averages, percentile ranks, and measures of spread. The researcher can summarize the variables in a
,data set one at a time, as well as examine how the variables are interrelated (e.g., by examining
correlations). The key question in descriptive statistics is how researchers can communicate the essential
characteristics of the data.
In organizing a data set - correct answer ✔✔Each participant gets a row, each variable gets a column
Graphs - correct answer ✔✔pictorial representations of data in two-dimensional space. Many graphs
display the data on two dimensions or axes. These two axes are the x- and y-axes, where the x-axis is the
horizontal dimension and the y-axis is the vertical dimension. When graphing the data for a single
variable, the values of this variable are represented on the x-axis, and the frequencies or percentages are
represented on the y-axis. If two variables are being graphed, the values of the independent variable are
put on the x-axis, and the values of the dependent variable are put on the y-axis. Graphs can also be
constructed for more than two variables.
Bar Graphs - correct answer ✔✔bar graph is a graph that uses vertical bars to represent the data
Notice that the x-axis of the bar graph represents the variable called "College Major" and the y-axis
represents "Frequency of occurrence." The bars provide graphical representations of the frequencies of
the three different college majors.
Histograms - correct answer ✔✔a graphic presentation of a frequency distribution
Bar graphs are used when the variable is a categorical variable. However, if your variable is a quantitative
variable, a histogram is preferred
It is especially useful because it shows the shape of the distribution of values. Compare the table of
starting salaries (on the right) with the associated histogram (on the left) using the same data set.
Line Graphs - correct answer ✔✔a format for illustrating data that relies on the drawing of one or more
lines
One useful way to draw a graphical picture of the distribution of a variable is to construct a line graph, a
format for illustrating data that relies on the drawing of one or more lines. An example line graph of
, grade point average (from the college student data set) is featured below. This type of graph is known as
a frequency polygon.
Consider the following line graph to see the type of line graph that is commonly constructed in factorial
research designs.
The dependent variable is placed on the vertical axis, one of the independent variables is placed on the
horizontal axis, and the categories of a second independent variable are represented by separate lines.
Another common use of line graphs is to show trends over time. In this case, the variable that a
researcher wishes to observe changing over time is placed on the vertical axis, and time is placed on the
horizontal axis. The key point is that there is not just one type of line graph. Line graphing is a versatile
tool for educational researchers.
Scatter Plots - correct answer ✔✔a way to visualize the relationship between two quantitative variables.
The dependent variable is represented on the vertical axis, and the independent variable is represented
on the horizontal axis. Dots are plotted within the graph to represent the cases (i.e., individuals).
Questions when dealing with scatter plots:
1. Does there appear to be a relationship between the two variables?
2. Is it a linear relationship or a curvilinear relationship?
3. If there is a relationship, how strong is it?
4. If a linear relationship is present, is it positive or negative?
measure of central tendency - correct answer ✔✔the single numerical value that is considered the most
typical of the values of a quantitative variable.
For example, if someone asked a teacher how well his or her students did on their last exam, using a
measure of central tendency would provide an indication of what a typical score was
Mode - correct answer ✔✔the most frequently occurring number in a set of data
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