Deck 6: Foundations of Statistical Inference

Question 1

In a normal distribution the portion of the curve above 1.96 standard errors is ______.

A) 1 percent
B) 5 percent
C) 10 percent
D) 2.5 percent

Answer 1

D

Question 2

A ______ allows the researcher to obtain measurements for all members of a population.

A) sample
B) census
C) parameter
D) distribution

Answer 2

B

Question 3

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 ______.

A) population
B) random sample
C) sample
D) universe

Answer 3

A

Question 4

The average amount given to a political candidate is an example of a ______.

A) sample statistic
B) population
C) sample
D) population parameter

Question 5

Random sampling error is defined as the extent to which a sample statistic differs from a population parameter by ______.

A) chance
B) bias
C) sloppiness
D) poor research design

Question 6

The US Census is an example of a ______.

A) sample
B) population
C) random sample
D) universe

Question 7

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?

A) 5'7
B) 6'1
C) 6'4
D) 5'4

Question 8

A public opinion poll reporting the president's job approval rating is an example of a ______.

A) sample statistic
B) population parameter
C) sample
D) census

Question 9

The level of random sampling error in a study is directly related to the ______ in the population characteristic.

A) people
B) ambiguity
C) variation
D) bias

Question 10

A ______ shows how random sampling error shapes the expected values of sampling statistics.

A) sampling distribution
B) standard deviation
C) unit of analysis
D) sampling frame

Question 11

Researchers study small groups of units of analyses to learn about the characteristics of a ______.

A) sample
B) population
C) universe
D) census

Question 12

In a normal distribution ______ percent of all scores fall with two standard deviations of the mean.

A) 99
B) 68
C) 50
D) 95

Question 13

A Z score is a method used to ______ the scores in a normal distribution.

A) standardize
B) report
C) measure
D) manipulate

Question 14

In statistical notation, the symbol σ refers to the ______.

A) sample size
B) variance
C) error
D) standard deviation

Question 15

A particular number of cases drawn from the entire group a researcher wishes to study is known as a ______.

A) population
B) universe
C) sample
D) census

Question 16

In a normal distribution, a Z score of 1.96 tells us what?

A) the sample size
B) the variance
C) how many standard deviations from the mean a sample mean is located
D) we need to increase our sample size

Question 17

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.

A) error; bias
B) size; variation
C) variation; error
D) bias; variation

Question 18

In statistical notation, the letter n refers to the ______.

A) standard deviation
B) variance
C) sample size
D) sampling error

Question 19

The interval within which 95 percent of all possible sample estimates will fall by chance is defined as ______.

A) lower confidence boundary
B) upper confidence boundary
C) the sample mean ±1.96 standard errors
D) the central limit theorem

Question 20

A researcher who wants to reduce the magnitude of random sampling error in her study by half should ______.

A) double the sample size
B) triple the sample size
C) quadruple the sample size
D) there is nothing she can do to reduce random sampling error

Question 21

The number of degrees of freedom is equal to the sample size, n, minus the number of parameters being estimated by the sample.

Question 22

Many of the variables of interest to political researchers are not measured at the nominal level.

Question 23

A normally distributed set of sample means resembles a standard bell curve.

Question 24

Random sampling errors are mistakes or oversights made by the researchers.

Question 25

The idea that an infinite number of samples drawn from a population will have normally distributed means is called the central limit theorem.

Question 26

As consumers of popular media, we are more likely to encounter arithmetic means than percentages or proportions.

Question 27

The standard error of a sample mean is synonymous with random sampling error.

Question 28

A standardized value is called a Z value or Z score.

Question 29

Variation in the population characteristic has a direct relationship with random sampling error: As variation goes up, random sampling error goes down.

Question 30

A researcher working with a sample size of 35 should use the Student's t distribution to make inferences about the population mean.

Question 31

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.

Question 32

Degrees of freedom are a statistical property of a large family of distributions, including the Student's t distribution.

Question 33

The larger the sample size, the lower the degrees of freedom, the more relaxed the t distribution.

Question 34

The standard error of a statistic is a single number.