ECON 6300/7320/8300: Advanced Microeconometrics Tutorial 1: Stata and Basic Statistics
At the end of this tutorial you should be able to
• use Stata to read, manipulate and save data and workfiles
• use Stata to compute descriptive statistics
• use Stata to conduct hypothesis tests concerning a population mean
Problems:
1. The text file consumption.dta contains observations on the weekly family consumption expenditure
(CONS) and income (INC) for a sample of 10 families.
(a) Read the data into Stata
(b) Draw a scatter diagram of CONS against INC.
(c) On checking the data, you find that your assistant has recorded the weekly consumption expen- diture for Family 8 as $900 instead of $90. Correct this error and redraw the scatter diagram
(d) Compute the mean, median, maximum and minimum values of INC and CONS.
(e) Compute the correlation coefficient between CONS and INC. Comment on the result.
(f) Create the following new variables
DCONS = 0.5CONS
LCONS = log(CONS)
INC2 = INC2 √
SQRTINC = INC
(g) Delete the variable DCONS and SQRTINC from the workfile
(h) Delete this workfile.
2. At the Famous Fulton Fish Market in New York city, sales of whiting (a type of fish) vary from day to day. Over a period of several months, daily quantities sold (in pounds) were observed. These data are in the file fultonfish.dat. Description of the data is in the file flutonfish.def. Describe the first four columns.
(a) Use Stata to open the data file and name the series in the first four columns as date, lprice, quan and lquan
(b) Compute the sample mean and standard deviation of the quantity sold (quan).
(c) Test the null hypothesis that the mean quantity sold is equal to 7,200 pounds a day at the 5% level of significance. Be sure to state i) the null and alternative hypothesis, ii) the decision rule, iii) the test statistic, iv) the decision, and v) your statistical conclusion.
(d) Construct the 95% confidence interval for part (c)
(e) Label the variable lprice as “log(Price) of whiting per pount” and lquan as “log(Quantity)”. Then, plot lprice against lquan. Comment on the nature of the relationship between these two variables.
(f) Save this workfile to any folder on any drive.
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