Suppose an NGO has employed your team as consultants. They have raised money for infrastructure projects aimed at reducing child mortality in developing countries. You have done some preliminary literature search for them by reading latest publications from the World Health Organisation (WHO) and some recent research papers published in respected international journals', and identified that the NGO can be effective by invest- ing in the infrastructure that extends basic drinking water services and basic sanitation services to areas that do not have such services. The NGO has told you that they do not have sufficient resources to deal with two sets of infrastructure projects and asked you to advise them if they should concentrate on water or sanitation projects to be most effective in reducing child mortality. They have also told you that building infrastructure for basic drinking water or basic sanitation services for the same number of people cost the same. Your team is asked to give a recommendation on what the NGO should do. Suppose you only have access to 2017 data for a sample of low income countries (the data set that you compiled in tutorial 2). Using that data set, answer the following questions (all results should be rounded to two decimal points and all hypothesis tests should be done at the 5% level of significance)