# Calculating with time series

### The AllThatStats calculator allows various operations to support your modelling -> ATS tutorial

#### Standard operations by time series (addition, subtraction, division, multiplication)

For instance, to build an index on Brazil’s GDP, base year 2010:

```
- search for Brazil’s GDP
- copy the 2010 value
- change to the calculator menu
- find the formula generator, the one which shows Brazil’s GDP identifier already…
- divide it by the base year as stored in your clipboard (don’t forget to add the “/” first)
- and finally, multiply the formula by 100 to build the index number…
```

#### Statistical values

For any single time series some general statistical figures are calculated automatically:

```
- the minimum and maximum value
- the mean
- the standard deviation
- the co-variance
```

Ref. the above example: simply click to the corresponding icon beside the new calculated “Brazil GDP index number” series.

#### General transformations

The calculator also provides a powerful transformation tool which comes with a number of predefined hard wired functions:

```
- lag
- moving average
- interpolation of missing values
- forecast
```

and formulas:

```
- for calculating the difference per time series selected (t-(t-1)) and
- the rate of change (t/t-1): compounded or continuously compounded
```