question: public Double convertWalkDistanceToWalkTime ( double walkDistance ) { Double walkTime = null ; switch ( studyAreaCode ) { case 1 : double a = 5.858772e-01 ; double b = 1.070014e-02 ; double c = - 1.464301e-06 ; double d = 2.694900e-09 ; double wt = a + b * walkDistance + c * Math . pow ( walkDistance , 2 ) + d * Math . pow ( walkDistance , 3 ) ; walkTime = wt * 60 ; break ; default : break ; } return walkTime ; }
target:  Converts a given walking distance value (in meters) into a walking time  value (in sec).