In each of the following studies, (i) State whether the study is experimental or observational; (ii) State whether the study is comparative or description; (iii) If the study is comparative, identify the response variable and the explanatory variable. Study 1: A study monitors the occurrence of heart disease over a 5-year period in men randomized to each high fiber or low fiber diets. Study 2: An industrial pump manufacturer monitors warranty claims and surveys customers to assess the failure distribution of its pumps. Study 3: A biologist randomly selects fish in a river to determine the proportion of fish which show signs of health problems due to pollutants that were poured in the river upstream by a chemical plant. Study 4: A study from hospital records found that women who had low weight gain during their pregnancy were more likely to have low birth weight babies than women who had high weight gains during their pregnancy. The researchers also recorded the age and ethnicity of the women. 4. (12 points) Brazos county plans to survey 1000 out of the 60,000 registered voters in the county regard- ing their preference on the county paying a portion of the building of a new football stadium for Texas A&M University. A complete alphabetical list of the registered voters is available for selecting the 1000 participants. In each of the following scenarios, identify by name the type of sampling method being used. a. Out of the first 60 names on the list, one name is randomly selected. That person and every 60th person on the list after that person are then included in the survey. b. Each voter is randomly assigned a number between 1 and 60,000 with no repeats. The voters' names are then ordered from smallest to largest based on their assigned number. The first 1000 voters on the list are selected for the survey. c. The list of 60,000 voters is divided by into 10 separate lists by voting districts within the county. The 60,000 voters are randomly assigned a number between 1 and 60,000 with no repeats. The names on each of the 10 lists are then ordered from smallest to largest by the number assigned the voter. The first 100 names on each of the ten ordered lists are selected to be in the survey. d. The list of 60,000 voters is first divided into four lists consisting where the voter lived, the East, West, North, or South regions of the county. There are 120 voting precincts in the county with 30 precincts in each region. A random sample of 10 precincts is taken within each region and then a simple random sample of 25 votes is taken within each of the randomly selected precincts. The resulting 1000 voters are then interviewed in a personal survey.