1) Determine whether the evaluated group is a population or a sample

a) Based on a randomly selected group of 500 patients with high cholesterol, it was found that 67% have heart disease. Is this a population or a sample; explain your answer.

This is a population group. They are studying the complete set of or population of 500 patients with high cholesterol in order to determine those that have heart disease in this population.

b) An investigation of 150 randomly selected local restaurants concluded that 42% of local restaurants have serious health code violations. Is this a population or a sample; explain your answer.

This is a sample group. They choose 150 restaurants in order to determine a percentage of those that had serious health violations. They choose these restaurants to represent all the local restaurants, this makes it a sample.

2) Determine whether the given value is a statistic or a parameter.

a) A researcher determines that 42.7% of all downtown office buildings have ventilation problems. Is this a statistic or a parameter; explain your answer.

This is a statistic as it is the data collected by the researcher. Statistics are the data collected and describe or summarize something.

b) After taking the first exam, 15 of the students dropped the class. Is this a statistic or a parameter; explain your answer.

This is a parameter. A parameter describes an entire population, in this case the entire population was everyone in the class.

3) Identify the type of sampling used.

a) A tax auditor selects every 1000th income tax return that is received. What type of sample is this and why?

This is a simple random sampling. A simple random sampling happens when all that can be involved in the study have an equal chance at being included but are selected by a number. For instance every 100th student in the school. As long as every student is assigned a number then it is a simple random sampling....