Module 1: Textbook Flashcards
A sample is used in statistical decision-making to represent a
population
In statistics, a sample is represented by data derived from —- (5)
observations, outcomes, responses, measurements or counts.
A parameter is a (numerical) description of a measurable ——-. A parameter provides information about ——
- population characteristic
- an entire population
A statistic is a (numerical) description of a —-. A statistic provides information about a ——-.
- sample characteristic
- portion, or subset, of a population
If another sample was selected from the population, the statistic in question most likely will have ——, since ——-.
- a different value than before
- no two samples are likely to be exactly the same
Example of a parameter
A social worker would like to know the average income of residents of a low-income apartment project and conducts a census by going door-to-door to obtain data. The population is residents of the project and the income data is a parameter since it represents the entire population.
Example of a statistic
A school nurse selected 40 sixth-grade students at random from the school class list and measured their height to obtain an estimate of the average height of all sixth graders at the school. The average she calculated was a statistic since it provided information from a sample representing the population of sixth graders at the school.
Descriptive statistics help us
to simplify the resulting large amounts of data in a way that makes the data easier to grasp (for sample)
Ex of descriptive statistics
Consider many students’ least favorite statistic, the Grade Point Average (GPA). GPA can be used to summarize and describe a student’s performance across a large number of classes.
Inferential statistics are used to make —- about things we cannot directly measure, while descriptive statistics are used to —– that we have somehow collected.
- generalizations
- describe a set of data
Descriptive statistics example:
Apartment
The researcher who collected data about the average income of residents of an apartment project published her information in a professional journal that reported a summary of the data. This is an example of descriptive statistics since it involved the organization, summarization, and display of the data.
Inferential statistics example:
Height
The school nurse who collected data on heights of sixth-graders used the data to make an estimate of the average height of all sixth grade students at the school. This is another example of inferential statistics, using data from a sample to reach a conclusion about the larger population of students.
Quantitative data can either be presented as
The numbers can be either continuous or discrete.
Qualitative data are presented as names or categories. They can be —, but not —-. The data are descriptive only, and cannot be operated on —–.
- observed
- measured
- mathematically
Nominal data
categories+numbers?
They can only be used as categories based on names, labels or qualities. The categories are mutually exclusive, meaning all cases must be sorted into one or another category with no overlap. Numbers may be used as labels but have no additional meaning or operability.
Examples of Nominal data
A list of postal codes represents nominal data. The codes may be shown as numbers or combinations of letters and numbers but have no mathematical properties; they only serve as identifiers.