statawalk1 - Stata Walkthrough: Exploring and Describing...

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Stata Walkthrough: Exploring and Describing Data This is an optional assignment, intended to get you accustomed to working with data in Stata. To do this assignment, you will need to go to my webpage and download the database of SAT scores by U.S. states. 1. Open the database using the menus ( or open it directly from your computer ) . 2. Type describe to look at the types of variables and their labels. float are normal, continuous values; int and byte take discrete numerical values; str have text. You will also see the labels attached to each variable, which should explain what they measure 3. Type list to view all of the observations in your database. You will see the state’s name, poverty rate, percentage of students taking the SAT, scores on the test, and per student spending for each state. 4. Type summarize to get some important summary statistics for each state ( the mean, standard deviation, minimum and maximum ) . Note that you have zero ( numerical ) values for the state name, so Stata does not give you summary statistics for this variable. 5. Type summ spend, detail to get detailed summary statistics for this variable. In the “Percentiles” column, you determine the lower and upper quartiles ( 25 th percentile is $ 6409; 75 th percentile is $ 8700.50 ) as well as the median ( 50 th percentile is $ 7080.50 ) . The mean, standard deviation, and variance are also shown. 6. You can use Stata as a calculator by typing “display” followed by some expression. ( The commands for basic operations are standard: +, - , *, /, and ^ for exponents. Stata understands parentheses, and knows to always Please Excuse My Dear Aunt Sally. ) To confirm that the standard deviation is the square root of the variance, type display (1205623)^(0.5) . 7. You might be curious if spending is correlated with some other variables. Type corr spend pover percent sat to obtain a table of all the correlation coefficients between the variables. In the first column, you can tell that there is a moderate negative correlation between spending and poverty rates ( states with higher poverty rates tend to spend less per student ) , a moderate positive correlation between spending and the percentage who take the test ( states that spend more tend to have more students who take the
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This note was uploaded on 03/19/2010 for the course ECON 400 taught by Professor Turchi during the Spring '08 term at UNC.

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statawalk1 - Stata Walkthrough: Exploring and Describing...

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