The median class for the given data is
Height(in cm)Less than 140Less than 145Less than 150Less than 155Less than 160Less than 165Cumulative Fequency41129404651
145-150
The given table can be written as:
Height(in cm)Less than 140140−145145−150150−155155−160160−165Cumulative Fequency41129404651
Since there are a total of 51 observations, the median class is the one whose cumulative frequency is closest to and greater than 25.5. Thus, the class interval 145-150 is the required answer.