Computer lab #1 Feb 20th, 2009Input data into STATA & Descriptive StatisticsSTATA commands in today’s classMIT OpenCourseWarehttp://ocw.mit.edu 11.220 Quantitative Reasoning & Statistical Methods for Planners I Spring 2009 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.1 11.220 Quantitative Reasoning and Statistical Methods for Planning Computer lab #1 Feb 20th, 2009 Input data into STATA & Descriptive Statistics STATA commands in today’s class cd Change directory dir or ls Show files in current directory insheet Read ASCII (text) data created by a spreadsheet (.csv) infile Read unformatted ASCII (text) data (.raw or .txt) infix Read ASCII (text) data in fixed format (.fix) input Enter data from keyboard describe Describe contents of data in memory or on disk compress Compress data in memory save Store the dataset currently in memory on disk in Stata data format use Load a Stata-format dataset (filename.dta) count Show the number of observations list List values of variables clear Clear the entire dataset and everything else memory Display a report on memory usage set memory Set the size of memory browse Check the input to your dataset without editing run Run a do. file list List the contents of a dataset codebook Detailed contents of a dataset log Create a log file summarize Descriptive statistics tabstat Table of descriptive statistics table Create a table of statistics stem Stem-and-leaf plot graph High resolution graphs kdensity Kernel density plot sort Sort observations in a dataset histogram Histogram for continuous and categorical variables tabulate One- and two-way frequency tables correlate Correlations pwcorr Pairwise correlations type Display an ASCII file2 11.220 Quantitative Reasoning and Statistical Methods for Planning Scripts we use in the real Command Window Note: STATA is case-SENSITIVE! cd E:\MIT\09Spring\STATALAB\DATA (change this part to your own local directory) dir insheet using hs0.csv insheet gender id race ses schtyp prgtype read write math science socst using hs0_noname.csv, clear infile gender id race ses schtyp str10 prgtype read write math science socst using hs0.raw, clear infix id 1-2 a1 3-4 t1 5-6 gender 7 a2 8-9 t2 10-11 tgender 12 using schdat.fix, clear describe compress save hsb10,replace memory set memory 5m Descriptive Statistics and Basic Plotting use hs0, clear describe /*talk about value label, white = 1, Asian = 2, etc*/ list list gender-read codebook summarize summarize read math science write summarize write, detail sum write if read>=60 sum write if prgtype=="academic" / * == is not =*/ Do use quotation mark for string sum write in 1/40 /specify the range, from 1 to 40/ tabulate prgtype, summarize(read) tab prgtype, summarize(write) /* note: tab is abbreviation of tabulate */ tabstat read write math, by(prgtype) stat(n mean sd) tabstat write, stat(n mean sd p25 p50 p75) by(prgtype) stem write histogram write, normal kdensity write, normal graph box write graph box write, over(prgtype) /* here it is over() instead of by(), if use by there will be 3 separate graphs*/ correlate write read science pwcorr write read science, obs scatter write read scatter write read, jitter(2) graph matrix read science write, half graph matrix read science write, half by(prgtype) Note: With reference to Bruin, J. 2006. newtest: command to compute new test. UCLA:Academic Technology Services, Statistical Consulting