First of all, we need to expand the data set so the time variable is in the right form. When we expand the data, we will inevitably create missing values for other variables. The second step is to replace the missing values sensibly. The examples shown here use Stata’s command tsfill...
to use time-dependent variables to represent the number of days on treatment, to minimise the potential for survival or immortality time bias i.e. must survive to get a drug. I have expanded my data set to create several time points per individual and used a variable to determine whether ...
Assumption #3: You should have independence of observations (i.e., independence of residuals), which you can check in Stata using the Durbin-Watson statistic. Assumption #4: There needs to be a linear relationship between (a) the dependent variable and each of your independent variables, and...
If you find a graph that you wish to create with your own data, you can take the command from the box and replace the variable names in the example with your own variable names. Buscha's book has two unique features that distinguish it from other books about Stata graphs. First, the...
that Stata maps onto the state of the RNG. The state of an RNG corresponds to a spot in the sequence. The mapping is not one to one because there are more states than seeds. If you want to pick up where you left off in the sequence, you need to restore the state, as in the ex...
In summary, there are several ways to drop observations from a dataset in Stata. The choice of method depends on the type of data and the desired outcome. What dropped variable? A dropped variable is a variable that has been removed or excluded from the dataset during the pre-processing sta...
First, we will just perform the normalization directly in the middle of our analysis script. In Stata, we call analysis scripts do-files because they do something. Let’s normalize the variable namedx. I don’t like to change the content of existing variables, so I am going to create a...
Enter the following formula in cell I5: =MylastrowFunction(H5,B5:F15,5) Explanation: This user-defined VBA function loops through each cell in the specified range and checks if it matches the value. It updates the variable to the current row number when a match is found. Finds the last...
Instead I would prefer to use isDate() function inside the loop to check the cells for being an actual date and increment the count variable each time you get a TRUE result. Finally return a count of cells containing the date instead of an array which will have to be used with more fu...
Similar to how text files are stored with a txt extension, excel sheets with xlsx, and Word documents with docs, stata also stores the data with a dta