STAT 200 Measures of Central Tendency and Dispersion Statistics Worksheet
University of Maryland Global Campus
STAT200 – Assignment #1: Descriptive Statistics Data Analysis Plan
Identifying Information
Student (Full Name):
Class:
Instructor:
Date:
Remove all redtext instructions from this template prior to submission. Save the file as a word document or pdf with the title “LAST_NAME – Assignment 1” (do not submit a rtf file).
Scenario: Please write a few lines describing your scenario and the four variables (in addition to income) you have selected.
Use Table 1 to report the variables selected for this assignment. Note: The information for the required variable, “Income,” has already been completed and can be used as a guide for completing information on the remaining variables. In the subsequent section, explain why you selected each variable as well as the expected outcome.
Table 1. Variables Selected for the Analysis
Variable Name in the Data Set  Description
(See the data dictionary for describing the variables.) 
Type of Variable
(Qualitative or Quantitative) 
Variable 1: “Income”

Annual household income in USD.  Quantitative 
Variable 2:  
Variable 3:  
Variable 4:  
Variable 5: 
Reason(s) for Selecting the Variables and Expected Outcome(s):
 Variable 1: “Income” –
 Variable 2: “ “ –
 Variable 3: “ “ –
 Variable 4: “ “ –
 Variable 5: “ “ –
Proposed Data Analysis:
Measures of Central Tendency and Dispersion
CompleteTable 2. Numerical Summaries of the Selected Variables and briefly explain why you choose those measurements. Note: The information for the required variable, “Income,” has already been completed and can be used as a guide for completing information on the remaining variables.
Table 2. Numerical Summaries of the Selected Variables
Variable Name  Measures of Central Tendency and Dispersion  Rationale for Why Appropriate 
Variable 1:
“Income”

● Median
● Sample Standard Deviation 
I am using median for two reasons:
1. If there are any outliers or the data is not normally distributed, the median is the best measure of central tendency. 2. The variable is quantitative.
I am using sample standard deviation for three reasons: 1. The data is a sample from a larger data set. 2. It is the most commonly used measure of dispersion. 3. The variable is quantitative.

Variable 2:  
Variable 3:  
Variable 4:  
Variable 5: 
Graphs and/or Tables
Complete Table 3. Type of Graphs and/or Table for Selected Variables and briefly explain why you choose those graphs and/or tables. Note: The information for the required variable, “Income,” has already been completed and can be used as a guide for completing information on the remaining variables. Note: Do NOT simply copy this for the remaining quantitative variables. Make a logical selection based on the data type.
Table 3. Type of Graphs and/or Tables for Selected Variables
Variable Name  Graph and/or Table  Rationale for why Appropriate? 
Variable 1:
“Income”

Graph: Histogram  A histogram is one of the best plots available to visually depict the distribution of quantitative level data. 
Variable 2:  
Variable 3:  
Variable 4:  
Variable 5: 
STAT200 Introduction to Statistics
Dataset for Written Assignments
Description of Dataset:
The data is a random sample from the US Department of Labor’s 2016 Consumer Expenditure Surveys (CE) and provides information about the composition of households and their annual expenditures (https://www.bls.gov/cex/). It contains information from 31 households, where a survey responder provided the requested information; it is all selfreported information. This dataset contains four socioeconomic variables (whose names start with SE) and four expenditure variables (whose names start with USD).
Description of Variables/Data Dictionary:
The following table is a data dictionary that describes the variables and their locations in this dataset (Note: Dataset is on second page of this document):
Variable Name  Location in Dataset  Variable Description  Coding 
UniqueID#  First Column  Unique number used to identify each survey responder  Each responder has a unique number from 130 
SEMaritalStatus  Second Column  Marital Status of Head of Household  Not Married/Married 
SEIncome  Third Column  Annual Household Income  Amount in US Dollars 
SEAgeHeadHousehold  Fourth Column  Age of the Head of Household  Age in Years 
SEFamilySize  Fifth Column  Total Number of People in Family (Both Adults and Children)  Number of People in Family 
USDAnnualExpenditures  Sixth Column  Total Amount of Annual Expenditures  Amount in US Dollars 
USDFood  Seventh Column  Total Amount of Annual Expenditure on Food  Amount in US Dollars 
USDHousing  Eighth Column  Total Amount of Annual Expenditure on Housing  Amount in US Dollars 
USDTransport  Ninth Column  Total Amount of Annual Expenditure on Transportation  Amount in US Dollars 
How to read the data set: Each row contains information from one household. For instance, the first row of the dataset starting on the next page shows us that for the first household in the sample: the head of household is not married and is 35 years old, has an annual household income is $97,469, has a family size of 4, annual expenditures of $54,929, and spends $6,900 on food, $18,514 on housing, and $145 on transportation.
UniqueID#  SEMaritalStatus  SEIncome  SEAgeHeadHousehold  SEFamilySize  USDAnnualExpenditures  USDFood  USDHousing  USDTransport 
1  Not Married  97469  35  4  54929  6900  18514  145 
2  Not Married  97912  49  1  55704  6937  18619  152 
3  Not Married  96697  49  2  56453  6971  18520  136 
4  Not Married  96653  51  4  56488  6943  18838  124 
5  Not Married  96664  53  3  55558  7051  18502  168 
6  Not Married  95744  52  4  55963  7040  18435  146 
7  Not Married  94929  59  2  55247  6948  18483  133 
8  Not Married  96928  43  3  55932  6953  18701  145 
9  Not Married  97681  53  4  56124  7097  18676  134 
10  Not Married  96244  56  4  56051  7073  18484  141 
11  Not Married  96886  44  2  55321  6982  18312  153 
12  Not Married  96727  39  2  56440  7051  18376  120 
13  Not Married  96690  57  2  56097  6822  18334  135 
14  Not Married  96572  59  2  56515  7179  18648  123 
15  Not Married  98717  40  3  56393  7036  18389  114 
16  Married  106292  57  4  82299  10983  23063  132 
17  Married  95801  54  3  73798  9395  23155  151 
18  Married  95385  50  4  74110  9101  22847  211 
19  Married  95865  46  1  74789  9321  22621  168 
20  Married  109312  37  6  80801  10564  25392  58 
21  Married  114051  42  5  84486  10820  25728  167 
22  Married  110651  58  4  83766  11226  22899  113 
23  Married  107338  67  2  83651  11710  21893  47 
24  Married  101829  45  4  82385  10821  22409  121 
25  Married  102244  34  4  74687  8735  27964  60 
26  Married  113558  31  5  79861  10346  25006  141 
27  Married  100947  35  4  73973  8455  26783  36 
28  Married  107369  66  2  83441  11724  23174  82 
29  Married  106894  51  5  81585  11360  22396  162 
30  Married  97769  47  5  73950  9035  22867  202 
31  Married  98885  45  4  57795  9653  23400  152 
STAT200 Introduction to Statistics
Assignment #1: Descriptive Statistics Data Analysis Plan
Assignment #1: Prepare Descriptive Statistics Data Analysis Plan
Before conducting any statistical analyses, researchers develop a plan for how they will analyze their data to answer their research questions. The purpose of this assignment is to provide an experience developing a descriptive statistics analysis plan. Note: This first assignment is a plan only; no statistics will be calculated or graphs created. The second assignment will involve carrying out the plan, after receiving feedback from your instructor.
Assignment Steps:
Step #1: Review the provided STAT200 data set file. (Note: This data set will be used for all three of this term’s written assignments).
The provided data set is a subsample of 31 data points from the US Department of Labor’s Consumer Expenditure Surveys (CE) and provides information about the composition of households and their annual expenditures (https://www.bls.gov/cex/). Detailed information on the sample and variables is included with the data set file; please carefully review this information to familiarize yourself with the data (Note: This information will be used in Assignment #2 to describe the dataset).
Step #2: Develop descriptive statistics data analysis plan.
 Task 1: Develop scenario. Imagine that you are head of a household and have to determine a household budget plan based on the data available from the dataset. For instance, you are a 35 year old single parent with a high school diploma and one child.
The “scenario” you describe is just to explain why you might be motivated to do this analysis. It does NOT have to be correct and/or true. As an example:
*Note that this is an example and that the data variables may not be the same as in our data set. You MUST create the scenario using the variables in our data set.*
“I am a 35 year old married parent (head of household) with one child. I earn $97,000 per year, and I spend $8,200 per year on food (including dining out): $1,800 of it is on meat, $0 on bakery items, and $150 on fruits (I’m on the Keto diet, so I spend more on protein than carbs). I want to determine how my income and expenditures relate to other people in the United States.”
You could also do something like this (but realize that this statement uses variables that are
NOT in our data set):
“I’m a 16year old medical doctor (child prodigy) who makes $248,000 a year. I have no kids, but I do have some college debt to pay off ($2,648 per month–med school is expensive!). I also
STAT200: Written Assignment #1 – Descriptive Statistics Data Analysis Plan – Instructions Page 1 of 5
have pay for food ($12,400–I eat out a lot), electricity ($6,400–I keep my apartment chilled), and transportation ($600–I don’t have a car yet). I want to learn how my current situation matches up to or differs from other people.”
This statement is probably not true, but it will make me smile while reading it. 🙂 The last statement is important, though. No one analyzes data sets for fun (even I don’t do that), so briefly explain why you are undertaking this process (other than you are told to do it for this class).
(NOTE: You do not need to put your actual income or any expenditure values in here–that is personal information that I do not need to know).
A key point here is to ensure you use variables from the data set that accompany our section.
The variables described above may not actually apply to our section (they are “general” or “generic”).
 Task 2: Select variables for analysis that match the scenario developed in Task 1. The data set provides information on household consumption; there are socioeconomic variables and expenditures variables. The socioeconomic variable names start with “SE” and the expenditure variable names start with a “USD;” all expenditures are in US dollars. All students must use income as one variable. Select two additional socioeconomic variables (one qualitative and one quantitative) and two expenditures for your analysis that match the scenario you developed for Task 1.
For instance, using the example scenario of a 35 year old single parent with a high school diploma and one child, you could select “income,” “education,” and “number of children” as
socioeconomic variables and then pick two household expenditure items to show the distribution of costs and compare that with your income. For this assignment, though, only select variables that are included with our section’s data set (and income, education, and
number of children may or may not be in our data set; these are just example variables include to aid in understanding).
When selecting variables, think about the following three questions:
o Why am I choosing these variables?
o What interests me about these variables?
o What do I think will be the outcome?
Answer these questions in the section on the template labeled: “Reason(s) for Selecting the
Variables and Expected Outcome(s):”.
STAT200: Written Assignment #1 – Descriptive Statistics Data Analysis Plan – Instructions Page 2 of 5
 Task 3: Determine appropriate measures of central tendency and dispersion for the selected variables. For each quantitative variable, select at least one measure of central tendency and at least one measure of dispersion (Please see table below for list of measures). For the qualitative variable, select one measure of central tendency. When determining the measures of central tendency and dispersion, think about what is appropriate given the level of measurement and type of variable. Recommend referring to the text and information posted in our LEO classroom to help with this task (Note: you will use this information to provide a rationale for your choice of measures)
Measures of Central Tendency  Measures of Dispersion 
● Mean  ● Range 
● Mode  ● Sample Standard Deviation 
● Median  ● Variance 
 Task 4: Determine appropriate graph and/or table for each of the selected variables. Select one graph or table for each variable (Please see below table for list of graphs and tables). When determining the graphs and tables, think about what is appropriate given the level of measurement and type of variable. Recommend referring to the text and information posted in our LEO classroom to help with this task (Note: you will use this information to provide a rationale for your choice of graphs and/or tables).
Types of Graphs  Types of Tables 
● Pie Chart  ● Frequency Table 
● Bar Chart  ● Relative Frequency Table 
● Histogram  ● Grouped Frequency Table 
● Box Plots (also known as BoxandWhiskers Plot)  
STAT200: Written Assignment #1 – Descriptive Statistics Data Analysis Plan – Instructions Page 3 of 5
Step #3: Complete the “Assignment #1: Descriptive Statistics Data Analysis Plan Template.”
Remember, you will not be conducting any statistical analysis, drawing any graphs, or compiling any tables for the first assignment. Rather, you need to wait for feedback from your instructor on this assignment and use that feedback to complete Assignment #2.
Here are the main sections for this assignment (i.e., completing the plan template):
 Identifying Information. Fill in information on name, class, instructor, and date.
 In this section, briefly (23 sentences) describe the scenario you developed in Step #2, Task 1.
 Complete Table 1: Variables Selected for the Analysis. Enter information the variables selected for analysis in Step #2, Task 2. For each selected variable be sure to include its: name as listed in the data set, description, and variable type.
 Reason(s) for Selecting the Variables and Expected Outcome(s): In this section, for each selected variable, please answer the following questions:
 Why did I choose this variable?
 What interests me about this variable?
 What do I think will be the outcome?
 Complete Table 2. Numerical Summaries of the Selected Variables. Enter information on selected measures of central tendency and dispersion for each selected variable. Be sure to briefly explain why you choose those measurements. Note: The information for the required variable, “Income,” has already been completed and can be used as a guide for completing information on the remaining variables.
 Complete Table 3. Type of Graphs and/or Tables for Selected Variables. Enter information on selected graph and/or table for each selected variable. Be sure to briefly explain why you choose those measurements. Note: The information for the required variable, “Income,” has already been completed and can be used as a guide for completing information on the remaining variables.
 Assignment Submission: Save the file that contains your completed “Assignment #1:
Descriptive Statistics Data Analysis Plan Template” as a pdf or docx using the following format: “LastName, First Name – Assignment1.” Then, submit the file via the Assignments area in the LEO classroom in the “Assignment #1: Descriptive Statistics Data Analysis Plan” folder and wait for your instructor’s feedback.
STAT200: Written Assignment #1 – Descriptive Statistics Data Analysis Plan – Instructions Page 4 of 5
Grading Rubric for Written Assignment #1
Your instructor will use this grading rubric when grading your assignment submission:
Scenario and Selection of Related Variables:  
● Clear description of scenario  20%  
● Selected variables and reasons are appropriate for the scenario.  
Selection of Measures of Central Tendency and Dispersion  
For each variable:  30%  
● Appropriate measures selected.  
● Rationale is provided and appropriate.  
Selection of Graphs and/or Tables  
For each variable:  30%  
● Appropriate measures selected.  
● Rationale is provided and appropriate.  
Writing Quality:  
● Completes all sections of template.  20%  
● Writes clearly, concisely, and with few errors.  
STAT200: Written Assignment #1 – Descriptive Statistics Data Analysis Plan – Instructions Page 5 of 5