Read the context below and answer the questions. Recognizing the migration of consumers from offline to online, ABC Company has started its email marketing since last year. However, a preliminary study showed that only 40% of the consumers who receive the emails open the emails. The low open rate directly leads to a low response rate. A marketing consultant of ABC Company suggests that it may help to increase the email open rate by including emojis in the email subject lines. To test the effect of emojis, ABC Company conducted an experiment. To begin with, the company randomly selected 1000 of its consumers as the experimental group and another 1000 consumers as the control group. Then, they measured the open rate of the experimental group and that of the control group. 390 customers in the experimental group opened their emails while 410 customers in the control group opened the emails. After the initial measure, the company implemented the treatment to the experimental group they included emojis in the email subject lines in all the emails sent to the experimental group. After one month of the implementation of the treatment, the company measured the open rate again. Interestingly, 550 customers in the experiment group opened the emails while 490 customers in the control group opened the emails. ABC Company also observed an increased response rate. 350 customers in the experimental group and 320 customers in the control group responded to the emails. 1. Question 1: Experiments are the major methodologies to establish causal relationships. One critical issue in an experimental design is to include a control group. Why is it necessary to have a control group in an experiment (or what are the consequences if there is not a control group)? Explain with an example. 2. In the experiment described above, what is the independent variable, and what is the dependent variable? 3. What is the test (treatment) effect? Please show the procedure. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac). Read the context below and answer the questions. Recognizing the migration of consumers from offline to online, ABC Company has started its email marketing since last year. However, a preliminary study showed that only 40% of the consumers who receive the emails open the emails. The low open rate directly leads to a low response rate. A marketing consultant of ABC Company suggests that it may help to increase the email open rate by including emojis in the email subject lines. To test the effect of emojis, ABC Company conducted an experiment. To begin with, the company randomly selected 1000 of its consumers as the experimental group and another 1000 consumers as the control group. Then, they measured the open rate of the experimental group and that of the control group. 390 customers in the experimental group opened their emails while 410 customers in the control group opened the emails. After the initial measure, the company implemented the treatment to the experimental group they included emojis in the email subject lines in all the emails sent to the experimental group. After one month of the implementation of the treatment, the company measured the open rate again. Interestingly, 550 customers in the experiment group opened the emails while 490 customers in the control group opened the emails. ABC Company also observed an increased response rate. 350 customers in the experimental group and 320 customers in the control group responded to the emails. 1. Question 1: Experiments are the major methodologies to establish causal relationships. One critical issue in an experimental design is to include a control group. Why is it necessary to have a control group in an experiment (or what are the consequences if there is not a control group)? Explain with an example. 2. In the experiment described above, what is the independent variable, and what is the dependent variable? 3. What is the test (treatment) effect? Please show the procedure. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac)