Your friend Joan from New Zealand is currently taking statistics and has emailed you for help in understanding what mean, median, and mode are as well as the idea of variance and standard deviation. Write back to Joan by explaining what mean, median, and mode are and for what types of data they are suited for. Discuss the pros and cons of each. Provide Joan with simple examples to illustrate how mean, median, and mode are computed. Also, explain to Joan the purpose of variance. What does variance measure exactly