Section 1.1: The Structure of Data
To do at home - Read section 1.1, starting with page 4; then, answer the questions.
1) What is statistics?
Statistics is the science of collecting, describing, and analyzing data.
Read about CASES AND VARIABLES:
2) The subjects/objects that we obtain information from are called ______
3) What is a variable?
A STUDENT SURVEY DATASET – First day survey to students in an introductory statistics class, administered through many years.
4) Consider the table 1.1 (page 4) – from the STUDENT SURVEY dataset.
a. Each column on the dataset correspond to a different ______
b. Each row on the dataset correspond to a different ______
5) Use a complete sentence to explain what the first five columns of the second row of table 1.1 tell you about student 2.
2 / F / Yes / Academy / 46) The following table lists final exam grades for some of my Spring 2015 students for the different classes that I taught.
Grades
Male: 98 (Math 117A), 95 (Math 098), 75 (Math 117A)
Female: 99 (Math 093), 89 (Math 117A)
Display the information from the above table as a dataset with cases as rows and variables as columns. (use table 1.1 as a guide)
Read about CATEGORICAL AND QUANTITATIVE VARIABLES
7) Give your own example of a categorical and a quantitative variable.
a. Categorical b. Quantitative
APPLYING THE CONCEPTS:
8) Book Exercises for Section 1.1 – in the book, you do the odd numbered problems; here we are doing the even ones.
For the situations described in Exercises 1.1 to 1.6:
(a)What are the cases?
(b)What is the variable and is it quantitative or categorical?
1.2 - Record the percentage change in the price of a stock for 100 stocks publicly traded on Wall Street.
1.4 - Measure the shelf life of bunches of bananas (the number of days until the bananas go bad) for a large sample.
1.6 - Record whether or not the literacy rate is over 75% for each country in the world.
Read about EXPLANATORY AND RESPONSE VARIABLES
9) Read EXAMPLE1.8 - In Example 1.4, we considered the following three questions about relationships between variables in the AllCountries dataset. Identify the explanatory variable and the response variable if it makes sense to do so. (Check answers in the book)
(a) Do countries larger in area tend to have a more rural population?
(b) Is the birth rate higher in developed or undeveloped countries?
(c) What is the relationship, if any, between a country's government spending on the military and on health care?
APPLYING THE CONCEPTS:
10) Book Exercises for Section 1.1 – in the book, you do the odd numbered problems; here we are doing the even ones.
In Exercises 1.7 to 1.10, a relationship between two variables is described. In each case, we can think of one variable as helping to explain the other. Identify the explanatory variable and the response variable.
1.8 - Amount of fertilizer used and the yield of a crop
1.10 - Year and the world record time in a marathon
To do in class
11) Using DATA SETS from Wiley - Activity 1 - HOW TO ACCESS DATA SETS
Go to WileyPlus, click on Read, Study and Practice, scroll down and click on DATA SETS INDEX. Select the EXCEL file to access the data; try any data set. The problem here is that it’s not always clear what data was collected and what units were used.
A better option is to go to my website: http://faculty.montgomerycollege.edu/maronne/
Statistics page, fourth row.
The Data Set Index contains the description of the Data Sets
The Data Set contains the actual data (as shown in WileyPlus).
1) Access the ACS data. Look into the Data Set Index for a description of the data.
a. What does ACS stand for?
b. Give a summary DETAIL of the data.
c. How many cases are listed?
d. List each variable, the units, the codes used, and classify each variable as categorical or quantitative.
2) From the BIKE COMMUTE data show a table with 4 cases and two variables, one categorical and one quantitative; include units. What questions may we ask about a relation between two variables?
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