function predict( x ) {
		if ( !isArray( x ) || x.length !== _nFeatures ) {
			throw new TypeError( format( 'invalid argument. First argument must be an array of length %u. Value: `%s`.', _nFeatures || 0, x ) );
		}
		return _weights.innerProduct( x );
	}
Predict response for a new observation with features `x`.

@private
@param {NumericArray} x - feature vector
@throws {TypeError} first argument must be an array
@throws {TypeError} first argument must have length equal to the number of predictors
@returns {number} response value

@example
// Predict new observation:
var x = [ 2.3, 5.3, 8.6 ];
var yHat = accumulator.predict( x );