Final Prep
The area under the normal distribution curve represents ________________.
100% of the sample or population
In a normal distribution the portion of the curve above 1.96 standard errors is ___________________.
2.5%
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
In a normal distribution ______________ percent of all scores fall with two standard deviations of the mean.
95
In the equation y = a + b(x) which variable represents the y-intercept?
A
Z-table (p.144 of the text book) gives you the proportions of the Normal Curve __________________ the Absolute Value of Z.
Above
Suppose that Democrats are more likely than Republicans to support abortion rights. Now suppose that women are more likely than men to support abortion rights. Finally, assume that women and men comprise an equal percentage of Democrats and Republicans. What effect are partisanship and gender having on support for abortion rights?
Additive
A researcher hypothesizes that individuals differ in their support for free speech based upon partisanship. He controls for gender and finds that women are more supportive than men for both Democrats and Republicans. What's going on here?
Additive relationship
The idea that an infinite number of samples drawn from a population will have normally distributed means is called the _____________________.
Central Limit Theorem
Random sampling error is defined as the extent to which a sample statistic differs from a population parameter by ____________.
Chance
A researcher studying partisan attitudes towards the use of contraceptives finds stark differences between men and women within the same party. This is an example of a ___________________.
Compositional Difference
A researcher hypothesizes that partisanship is closely related to individual attitudes regarding same-sex marriage. To be sure the researcher should _______________ for any additional explanations.
Control
A researcher examining partisan differences on gun control opinions while holding gender constant is conducting a _______________________.
Controlled Comparison
A relationship between a causal variable and a dependent variable within one value of another causal variable is known as a ______________________.
Controlled Effect
The size and effect of the independent variable on the dependent variable is estimated by the __________________ coefficient.
Correlation
A researcher working with data about individuals' ages and their income wants to know how income is related to age. Does income go up or down or remain constant with age? Which analysis would help the researcher understand this relationship best?
Correlation analysis
A table that displays the values of the independent variable on the columns and the values of the dependent variable on the rows is known as a __________________?
Cross-Tab
A researcher is studying the attitudes of liberals and determines that one characteristic of liberals is support for abortion rights. Joe describes himself as a liberal so the researcher concludes that Joe supports abortion rights. This is an example of ______________________.
Ecological fallacy
When the results of a laboratory experiment cannot be generalized to the outside world the study is said to lack ___________________________________.
External Validity
A controlled comparison is done by examining the relationship between an independent variable and a dependent variable while allowing the values of other variables to fluctuate.
False
Controlled comparisons between two interval level variables are displayed in a cross-tabulation.
False
Correlation analysis produces a statistic that estimates the size of the effect of the independent variable on the dependent variable.
False
If the two groups in an experimental design are the same in every way except on the dependent variable it is a well-designed experiment.
False
In a hypothesis testing situation, dependent variable is the cause and an independent variable represents the effect.
False
In the Z test formula for difference of means above, the second part of the numerator (mu1 minus mu2) takes a value of zero if the hypothesis test reveals evidence in support of Ha (the alternate hypothesis).
False
In the equation y = a + b(x), x represents the value of the dependent variable.
False
Pearson's correlation coefficient is applicable universally, irrespective of the type of measurement of the variables involved
False
Random sampling error is one way to measure the amount of dispersion in a sample.
False
The purpose of a cross-tabulation is to explain how the dependent variable affects the independent variable.
False
When examining gun control attitudes and partisanship a researcher notices that partisanship loses its explanatory power when gender is considered. This means an interactive relationship is present.
False
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
A __________________ is a testable statement about the empirical relationship between cause and effect.
Hypothesis
"Explanatory variable" is another name for _________________ variable.
Independent
If a control variable has a large effect on one category of an independent variable but a small effect on another category of the independent variable then _____________ is present.
Interaction
The rule of direction for nominal relationships helps us identify _______________.
Interaction relationships
If a control variable has a large effect on one category of an independent variable but a small effect on another category of the independent variable then _____________ is present
Interactive
Suppose that for women (Z) partisanship (X) has a weak effect on support for same-sex marriage (Y) but for men it has a strong effect. What kind of relationship is gender exerting on the relationship between partisanship and attitudes towards same-sex marriage?
Interactive
A researcher who wants to learn the precise differences between her units of analysis will likely use a(n) ______________ level variable to code the characteristics.
Interval
Every time a sample mean produces a negative z-score, you should reject the null hypothesis.
No
A researcher studying the ratings of men and women toward the Democratic Party hypothesizes that women will give Democrats a higher rating than will men. The female mean rating is 52.5 with a standard error of 1.2 points. The male mean rating is 47.1 with a standard error of 1.6 points. Should the researcher reject the null hypothesis?
No, because the lower boundary for women overlaps the upper boundary for men
The ________________ is stated to remind us that the observed results of a sample could be the result of random error.
Null Hypothesis
When two or more independent variables are exerting an effect on the dependent variable each is said to have a(n) ________________ effect.
Partial
Suppose a researcher is plotting the median age and voter turnout rate for each of the fifty states. If states with a higher median age have higher voter turnout rates what type of relationship exists between the variables?
Postive
A research assistant is entering data into a dataset on individual attitudes regarding social issues. He did not get enough sleep the night before and o
Random Error
In the equation y = a + b(x), b stands for the _______________.
Regression coefficient
The formula y = a + b(x) represents the ________________.
Regression line
The level of random sampling error in a study is inversely proportional to the _____________ .
Sample Size
A researcher studying college GPA's hand picks 50 of her best known students to determine the average GPA of political science majors at her university. What error has she introduced to her study?
Selection Bias
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
A relationship between X and Y that disappears when controlling for Z is said to be __________________.
Spurious
If a researcher is examining the relationship between X and Y but finds that the relationship dissipates when controlling for Z it means the relationship between X and Y is __________________.
Spurious
A Z score is a method used to ________________ the scores in a normal distribution.
Standardize
A researcher working with a sample size of 35 should use the ___________________ to make inferences about the population mean.
Student's t-distribution
To determine the direction of a nominal relationship it is necessary to ____________.
Subtract the other values from the left-most column of a variable value
A researcher is studying the formation of political attitudes in a group of individuals. Some of the individuals are exposed to several fake news stories to determine if the stories affect their attitudes while others are not. The exposed individuals are called the __________________.
Test Group
When comparing two sample means we can safely reject the null hypothesis if ____________________.
The confidence intervals do not overlap
Please discuss the core goals of inferential statistics. Make sure you respond in two or three properly constructed sentences with a level of clarity that your explanation would make sense to a lay person.
The main goal of inferential statistics is to use the data available from samples to make predictions/estimates about population parameters. Inferential statistics comprises a set of procedures for deciding how closely a relationship we observe in a sample corresponds to the unobserved relationship in the population from which the sample was drawn
In a study of partisanship and attitudes toward social welfare spending while controlling for gender a researcher finds that women are 15 points more likely than men to support social welfare spending. This is an example of ______________________.
The partial effect of gender
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
A hypothesis must identify the direction of causal relationship between an independent and the dependent variable.
True
A politician claiming that lowering tax rates produces higher revenues is a valid hypothesis.
True
A simple comparison of two variables provides a zero-order relationship.
True
An interviewer who records a respondent's answer incorrectly has introduced random measurement error into the research.
True
Pearson's r is a measure of association known as a correlation coefficient
True
Sampling frame refers to the method of defining the population a researcher wishes to study.
True
The confidence interval method of hypothesis test will always yield same results as the p-value method of hypothesis test.
True
The y-intercept is the value of y when x equals zero.
True
n an interactive relationship, the relationship between X and Y depends on the value of Z.
True
The eyeball test of significance allows us to reject the null hypothesis if the sample difference is _______________.
Two or more standard errors from zero
A researcher who concludes that a relationship exists between X and Y when it does not has committed a ________________.
Type I error
A researcher studying welfare policy support believes women are more supportive than men. In this case, the null hypothesis--> In a study of individuals, women are more likely than men to support welfare policy.
Wrong
For large sample sizes, the Student's t-distribution significantly diverges from the standard normal distribution (z).
Wrong
Sample proportions, in a statistical sense, are sample means!
Yes
In a scatterplot the ____________ [A] variable is measured on the horizontal axis and the ______________ [B] variable is on the vertical axis.
[A]Independent [B]Dependent
When the results of a laboratory experiment cannot be generalized to the outside world the study is said to lack _____________________________
external validity
The ______________ allows the researcher to determine the exact probability of a particular result occurring by chance.
p-value approach
A researcher believes that political attitudes are influenced by education level. What is the dependent variable__________________?
political attitudes
In any type of experiment it is essential that participants be _____________________ to ensure the absence of systematic/selection bias.
randomly assigned
