code: public double standardDeviation(String eventCollection, String targetProperty, Timeframe timeframe) throws IOException {
          Query queryParams = new Query.Builder(QueryType.STANDARD_DEVIATION)
                  .withEventCollection(eventCollection)
                  .withTargetProperty(targetProperty)
                  .withTimeframe(timeframe)
                  .build();
          return queryResultToDouble(execute(queryParams));
      }
docs: Standard Deviation query with only the required arguments.
  Query API info here: https://keen.io/docs/api/#standard-deviation
  
  @param eventCollection The name of the event collection you are analyzing.
  @param targetProperty  The name of the property you are analyzing.
  @param timeframe       The {@link RelativeTimeframe} or {@link AbsoluteTimeframe}.
  @return The standard deviation query response.
  @throws IOException If there was an error communicating with the server or an error message received from the server.