P2. Growth-Sales/Earning

X(t)is a time series. Growth function is to capture relative change(increase or decrease) ofX(t)wheretmeans this quarter andt-1mean last quarter.

Sales is the amount of money that a computer actually receives during a specific period, including discounts and deductions for returned merchandise. Sales are positive number in most cases with few exceptions.

Earnings are the amount of profit that a company produces during a specific period, which is usually defined as a quarter (three calendar months) or a year. Earnings can be positive and negative values.

Considering above description, please improve below formula of Sales/Earning Growth to processdirtydata values.

Earnings Growth Formula: { Earnings(t)/Earnings(t-1) }-1

Sales Growth Formula: { Sales(t)/ Sales(t-1) }-1

i.e. taking ratios between current quarter's value and last quarter's value and subtract by one