# Math Statistics

Chapter one
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.

The group of 500 patients is a sample. This is because it is taken from a larger group of patients with high cholesterol, which forms the population, i.e. from the larger population of high-cholesterol patients, a sample of 500 patients has been taken to represent the population in a study on prevalence of heart disease in this population, which was found to be 67%.

a.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.

The group of 150 local restaurants is a sample. This is because it was taken from a larger population of restaurants, i.e. from all local restaurants (population), a group of 150 restaurants had been selected as the sample to represent the population. From this sample it was determined that 42% of the population of restaurants had health code violations.

1.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.

The 42.7% is a parameter. A parameter is an unknown fixed number that describes an already determined quality of a population. The population in this case is unknown, and thus the fixed number in the population that is represented by 42.7% is also unknown. This is so because the value of 42.7% was obtained by studying a sample of the population, thus the inference from the study is a parameter of the population.

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

The value 15 is a...