In April 2018, a study was conducted to understand the role of Twitter. The study showed that Twitter helps business by illustrating the practical implications of a decision, connecting businesses to prominent technologies and trends—e Wom, big data, and smart cities— and identifying possible future directions. The practical implications of the study have a mean of 686 results and a standard deviation 66.
a. It can be guaranteed that 75% of businesses being connected to prominent technologies and trends will be in what interval?
b. Using the empirical rule, it can be estimated that approximately 95% of businesses being connected to prominent technologies and trends will be in what interval?