Conditional Loops (Loops)

In this final exercise you’ll use programming if, foreach, and continue to control what happens inside a loop based on sample size.

Goal: For a list of variables, automatically summarize and graph them, but skip variables that have too few non-missing observations. Start bv defining a local macro named vars with the following variables:

• yield_kg
• harvest_value_USD
• nitrogen_kg
• totcons_USD

1. Write a foreach and varlist to loop over vars. Inside the loop, for each variable v:
   • Run `qui sum `v', detail
   • Store the number of non-missing observations in a local N using r(N) (remember to use = so that the local equals the expression and not the literal text r(N)). Then, still within the loop, have Stata display the number of observations for each variable. How many observations are there for each variable?

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