1.1 An Overview of Statistics
Determine whether the data set is a population or a or a sample. Explain your reasoning. The height of each student in a classroom.
Population because it is a collection of heights for all the students in the classroom
A statistic is a measure that describes a population characteristic.
False; a statistic is a measure that describes a sample characteristics
Why is a sample used more often than a population?
It is usually impossible to count the entire population
Determine whether the underlined value is a parameter or a statistic. The average age of men who have walked on the moon was 39 years, 11 months, 15 days
Parameter
Determine whether the underlined value is a parameter or a statistic. In a study of all 4077 employees at a college it is found that 40% own a vehicle.
Parameter because the value is a numerical measurement describing a characteristic of the population
Determine whether the underlined value is a parameter or a statistic. Explain your reasoning. For a certain movie 64.3% of 112 members of the audience were females.
Parameter; because the data of all 112 audience members is a population
A survey of 12,098 men in a particular country found that 47.2% received an influenza vaccine for a recent flu season. Identify the population and sample.
Population: Immunization status of all men in the country Sample: Immunization status of the 12,098 men selected
In a poll 1,005 women in a country were asked whether they favor or oppose the use of federal tax dollars to fund medical research using STEM cells obtained from human embryos. Among the respondents 46% said they were in favor. Identify the population and sample.
Population: all women in the country Sample: the 1,005 women selected
Determine whether the data set is a population or a or a sample. Explain your reasoning. The ages of three families of people in an apartment building housing ten people.
Sample because the collection of ages for three families of people is a subset of all the people living in the building.
Determine whether the data set is a population or a or a sample. Explain your reasoning. The number of cars of 10 households in a neighborhood of 30 households.
Sample because the collection of the number of cars for 10 households is a subset of all households in the neighborhood
Determine whether the data set is a population or a or a sample. Explain your reasoning. The salary of 17 teachers in a school
This is a sample because it is a collection of salaries for some teachers in the school
In a recent study volunteers who had 8 hours of sleep were three times more likely to answer questions correctly on a math test than were sleep-deprived participants (a) Identify the sample used in the study (b) What is the sample population? (c) Which part of the study represents the descriptive branch of statistics? (d) Make an inference based on the results of the study
(a) The sample is the responses of the volunteers in the study (b) The population is the collection of the responses of all individuals who completed the math test (c) The statement three times more likely to answer questions correctly is an example of descriptive statistics (d) Individuals who are not sleep deprived will be more likely to answer math questions correctly than individuals who are sleep deprived
What is the difference between a parameter and a statistic?
A parameter is a numerical description of a population characteristic. A statistic is a numerical description of a sample characteristics
How is a sample related to a population?
A sample is a subset of a population.
Suppose a survey of 938 major appliance shoppers found that more than 30% bought extended warranties. Which part of the survey represents the descriptive branch of the statistics? Make an inference based on the results of the survey.
Descriptive: 30% of major-appliance shoppers in the sample bought extended warranties Inference: Most major-appliances shopper do not buy extended warranties
Suppose a survey of 531 women in the United States found that more than 57% are the primary investor in their household. Which part of the survey represents the descriptive branch of statistics? Make an inference based on the results of the survey.
Descriptive: 57% of women in the sample are the primary investor in their household Inference: There is an association between U.S. women and being the primary investor in their household.
Determine whether the data set is a population or a or a sample. Explain your reasoning. The number of floors in each building in a city
Population because it is a collection of the number of floors for all buildings in a city
Determine whether the data set is a population or a or a sample. Explain your reasoning. The number of floors in each home in a town
Population because it is a collection of the number of floors for all homes in a town
A study of 875 senior citizens shows that participants who exercise regularly exhibit less of a decline in the cognitive ability than those who barely exercise at all. From this study, a researcher infers that your cognitive ability increases the more you exercise. What is wrong with this type of reasoning?
The inference may incorrectly imply that exercise increases a persons cognitive ability the study shows a slower decline in cognitive ability
Determine whether the underlined value is a parameter or a statistic. Explain your reasoning. A survey of 2209 adults in a country found that 83% think that militant terrorists are a major threat of the well-being of their country
The number is a sample statistic because it describes the people in a sample which is a subset of all of the people in a country.
It is impossible for Census Bureau to obtain all the census data about the population of the United States.
The statement is true
The two main branches of statistics are:
descriptive statistics and inferential statistics
