Vocabulary
Every element in a group being considered.
What is a Population?
Is this "Average income of all people in a city, proportion of voters supporting a candidate" an example of a parameter or a sample?
Parameter
Which of the following represents a population and which represents a sample?
Population (1): The heights of all the players on the basketball team.
Sample (2): The heights of 10 randomly selected players from the team.
The ages of 5 students in a group are: 12, 14, 15, 13, and 16. What is the mean age of the students?
The mean age is 14
True or False: A parameter describes a characteristic of a sample, not the entire population.
False
A subset of the population which is used when it is not possible to access all elements of the population.
What is a Sample?
Define Parameter in your own words.
A parameter is a numerical value that describes a characteristic of an entire population. It is a fixed value, but often unknown because it's difficult to measure every member of the population.
True or False: A sample always represents the population exactly.
False.
A sample is a smaller group selected from the population, and it may not represent the population exactly. It’s used to make estimates about the population, but there can be some variation.
The test scores of 7 students are: 85, 90, 78, 92, 88, 94, and 84. What is the mean score? What is the Median score?
The mean score is approximately 87.29, and 88 is the median
A survey of 150 students finds that 60 like pizza more than pasta. What conclusion can be made from the survey? What percentage of people liked pizza more than pasta?
About 40%
A value that describes a population. A parameter is calculated from every element in a population.
What is a Parameter?
A researcher wants to find out the average amount of time people spend watching television each week. She surveys 1,000 people and calculates the average viewing time for the sample.
What is the population? What is the parameter?
Population: All people in the country (or the group of people the researcher is interested in).
Parameter: The average amount of time spent watching television per week by all people in the country.
A phone company wants to know the average battery life of their latest phone model. They test 100 phones and calculate the average battery life for the sample of phones.
What is the sample? What is the sample result?
Sample: 100 phones tested.
Sample result: The average battery life of the 100 phones tested.
The following data shows the number of pets owned by families: 1, 3, 2, 2, 4, 5, 3, 6, 2. Find the Mean, Median, and Mode of this data set.
median = 3
mean = 3.11
mode = 2
True or False: A population is always smaller than a sample.
False
(The population is always larger or equal to the sample.)
A value that estimates a parameter. Calculated from every element in a sample.
What is a Statistic?
Ms. Pearson takes a survey of 200 students at North Bend. She asks them if they would want to go on a field trip right before spring break?
What is the population? What is the Parameter?
Population: All the students who attend North Bend
Parameter: The actual number of voters that support going on a field trip right before spring break.
A car rental company wants to determine how many miles people drive on average when they rent a car. They survey 250 people who recently rented a car and calculate the average number of miles driven by the sample.
What is the sample? What is the sample result?
Sample: 250 people who recently rented a car.
Sample result: The average number of miles driven by the 250 surveyed people.
The following are the number of books read by 4 students: 5, 7, 3, and 8. What is the Mean Absolute Deviation (MAD)?
The MAD is approximately 1.75
A survey of 200 people finds that 50 prefer coffee over tea. What conclusion can be made from the survey? About what percentage of people prefer coffee over tea?
About 25%
What is a sample called when it accurately represents the characteristics of the population and produces valid inferences(there are two types of sample).
What is an Unbiased Sample?
A company wants to know the average salary of all employees in their organization. They survey 500 randomly selected employees and calculate the average salary of those employees.
What is the population? What is the parameter?
Population: All employees in the company.
Parameter: The average salary of all employees in the company.
What is the difference between parameter and sample?
A parameter is a value that describes a characteristic of an entire population, such as the true average or proportion for that group. A sample is a smaller subset of the population, and we use its results to estimate or make inferences about the population's parameter.
The following are the number of hours spent studying by 6 students in a whole week: 12, 18, 22, 15, 19, and 16. What is the Mean Absolute Deviation (MAD)?
The Mean Absolute Deviation (MAD) is approximately 2.67.
A survey of 80 workers finds that 10 commute by bicycle. What conclusion can be made from the survey? About what percentage of people surveyed commuted by bike?
About 12.5%