For example, has increasing fee-structure led to decreasing market share?
Hypothesis Testing: test hypothesis market share has decreased
Many statistical hypothesis test procedures available:
Z-test population mean
t-test population mean
Z-test population proportion
Z-test difference of two population means
t-test difference of two population means
Z-test difference of two population proportions
Chi-Square test independence among categorical variables
Analysis of variance F-test
t-test for the slope of a regression line
And many others, including tests for time-series analysis, quality control tests, and nonparametric tests