Quiz 6 Flashcards
A ______ allows the researcher to obtain measurements for all members of a population.
census
A ______ shows how random sampling error shapes the expected values of sampling statistics.
sampling distribution
A large group of people of particular interest that we desire to study and understand, such as the people in a city or persons with jobs, is called a ______.
population
A particular number of cases drawn from the entire group a researcher wishes to study is known as a ______.
sample
A public opinion poll reporting the president’s job approval rating is an example of a ______.
sample statistic
A researcher studying the height of college freshmen determines the average height of males to be 5’10 with a standard deviation of 1.5 inches. John has a Z score of +1.96, which means John is what height?
6’1
A researcher who wants to reduce the magnitude of random sampling error in her study by half should ______.
quadruple the sample size
A Z score is a method used to ______ the scores in a normal distribution.
standardize
In a normal distribution ______ percent of all scores fall with two standard deviations of the mean.
95
In a normal distribution the portion of the curve above 1.96 standard errors is ______.
2.5 percent
In a normal distribution, a Z score of 1.96 tells us what?
how many standard deviations from the mean a sample mean is located
In statistical notation, the letter n refers to the ______.
sample size
In statistical notation, the symbol σ refers to the ______.
standard deviation
Random sampling error is defined as the extent to which a sample statistic differs from a population parameter by ______.
chance
Researchers study small groups of units of analyses to learn about the characteristics of a ______.
population
The average amount given to a political candidate is an example of a ______.
population parameter
The interval within which 95 percent of all possible sample estimates will fall by chance is defined as ______.
the sample mean ±1.96 standard errors
The level of random sampling error in a study is directly related to the ______ in the population characteristic.
variation
The magnitude of random sampling error in a study depends upon the ______ of a sample and the amount of ______ in the population characteristic being measured
size; variation
The US Census is an example of a ______.
population
A normally distributed set of sample means resembles a standard bell curve.
True
A probability is defined as the likelihood of the occurrence of an event or set of events.
True
A researcher working with a sample size of 35 should use the Student’s t distribution to make inferences about the population mean.
True
A standardized value is called a Z value or Z score.
True
As consumers of popular media, we are more likely to encounter arithmetic means than percentages or proportions.
False
Degrees of freedom are a statistical property of a large family of distributions, including the Student’s t distribution.
True’
Many of the variables of interest to political researchers are not measured at the nominal level.
False
Random sampling errors are mistakes or oversights made by the researchers.
False
The idea that an infinite number of samples drawn from a population will have normally distributed means is called the central limit theorem.
True
The larger the sample size, the lower the degrees of freedom, the more relaxed the t distribution.
True
The number of degrees of freedom is equal to the sample size, n, minus the number of parameters being estimated by the sample.
True
The standard error of a sample mean is synonymous with random sampling error.
True
The standard error of a statistic is a single number.
True
Variation in the population characteristic has a direct relationship with random sampling error: As variation goes up, random sampling error goes down
False
When a variable is measured at the nominal or ordinal-level, we don’t calculate its dispersion but say dispersion is maximized when observations are evenly divided among possible values.
True
