A physician wants to test if temperature has an effect on heart rate. In order to do this, she compares the heart rate in beats-per-minute of several random volunteers after a period of time in a room with a temperature of 50 F and after a period of time in a room with a temperature of 75 F . Identify the null and alternative hypotheses for a hypothesis test, where each difference is calculated by subtracting the heart rate in the 75 F room from the heart rate in the 50 F room. Select the correct answer below: H 0 : d = 0 H a : d < 0 H 0 : d = 0 H a : d > 0 H 0 : d = 0 H a : d 0 H 0 : d > 0 H a : d = 0