Quiz 6

Question 1

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

Answer 1

census

Question 2

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

Answer 2

sampling distribution

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 ______.

Answer 3

population

Question 4

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

Answer 4

sample

Question 5

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

Answer 5

sample statistic

Question 6

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?

Answer 6

6’1

Question 7

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

Answer 7

quadruple the sample size

Question 8

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

Answer 8

standardize

Question 9

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

Answer 9

95

Question 10

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

Answer 10

2.5 percent

Question 11

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

Answer 11

how many standard deviations from the mean a sample mean is located

Question 12

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

Answer 12

sample size

Question 13

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

Answer 13

standard deviation

Question 14

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

Answer 14

chance

Question 15

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

Answer 15

population

Question 16

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

Answer 16

population parameter

Question 17

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

Answer 17

the sample mean ±1.96 standard errors

Question 18

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

Answer 18

variation

Question 19

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

Answer 19

size; variation

Question 20

The US Census is an example of a ______.

Answer 20

population

Question 21

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

Answer 21

True

Question 22

A probability is defined as the likelihood of the occurrence of an event or set of events.

Answer 22

True

Question 23

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

Answer 23

True

Question 24

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

Answer 24

True

Question 25

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

Answer 25

False

Question 26

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

Answer 26

True’

Question 27

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

Answer 27

False

Question 28

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

Answer 28

False

Question 29

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

Answer 29

True

Question 30

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

Answer 30

True

Question 31

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

Answer 31

True

Question 32

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

Answer 32

True

Question 33

The standard error of a statistic is a single number.

Answer 33

True

Question 34

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

Answer 34

False

Question 35

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.

Answer 35

True