Question 4. Random-digit dialing is often used to select telephone survey samples. This technique randomly selects the last four digits of a telephone number from a telephone exchange. (An exchange is the first three telephone numbers after the area code). This type of sample gets around the problem of using a telephone book as a sampling frame; however, other types of problems may still be encountered. Identify one type of selection biases that may ensue from this method

C=59(f−32) the equation above shows how temperature f, measured in degrees fahrenheit, relates to a temperature c, measured in degrees celsius. based on the equation, which of the following must be true? a temperature increase of 1 degree fahrenheit is equivalent to a temperature increase of 59 degree celsius. a temperature increase of 1 degree celsius is equivalent to a temperature increase of 1.8 degrees fahrenheit. a temperature increase of 59 degree fahrenheit is equivalent to a temperature increase of 1 degree celsius. a) i only b) ii only c) iii only d) i and ii only