Question 1

Which of these does not apply to a 'statistically significant' relationship between two categorical variables?

Accepted Answer

A) The relationship between the two variables is very important from a practical standpoint. 
B) The relationship observed in the sample was unlikely to have occurred unless there really is a relationship in the population. 
C) The notion that this relationship could have happened by chance is deemed to be implausible. 
D) All of the above apply to a 'statistically significant' relationship. 
A) The relationship between the two variables is very important from a practical standpoint. 
B) The relationship observed in the sample was unlikely to have occurred unless there really is a relationship in the population. 
C) The notion that this relationship could have happened by chance is deemed to be implausible. 
D) All of the above apply to a 'statistically significant' relationship. A

Question 2

For Questions , use the following narrative
Narrative: Teenage voting
Suppose you take a random sample of teenagers aged 18-19, and you find that 53% of the males in your sample are Democrats, and 54% of the females in your sample are Democrats, respectively.
-{Teenage voting narrative} Could these results ever be statistically significant? Why or why not?

Accepted Answer

Yes, if the sample size is large enough, any non-zero difference can become statistically significant.

Question 3

An interesting relationship in the population may fail to achieve __________ significance if there are too _____ observations.

Accepted Answer

statistical; FEW

Question 4

Another name for the alternative hypothesis is the __________ hypothesis.

Accepted Answer

The answer of Another name for the alternative hypothesis is...

Question 5

Suppose researchers say they 'failed to find a relationship' between two variables that they thought might have been related.What does this say to you, as an educated consumer of statistical information?

Accepted Answer

A) You should check to make sure the study was not based on a small number of individuals. 
B) The researchers must not have observed any relationship in their sample. 
C) There must be no relationship between these two variables in the population. 
D) All of the above. 
A) You should check to make sure the study was not based on a small number of individuals. 
B) The researchers must not have observed any relationship in their sample. 
C) There must be no relationship between these two variables in the population. 
D) All of the above.

Question 6

Your mother-in-law says that rubbing a carpet stain with toothpaste before applying stain remover helps take the stain out.You are skeptical.You asked an impartial neighbor to set up a randomized experiment to find out whether there is a relationship between the stain removing method and the outcome.She went home to collect and analyze the data, then called you and said "In a chi-square test, I would choose the alternative hypothesis," and then hung up.What do you conclude?

Accepted Answer

A) The toothpaste didn't make a difference. 
B) The toothpaste did help after all. 
C) The toothpaste had a significant effect but you don't know in which way yet. 
D) The toothpaste made things worse. 
A) The toothpaste didn't make a difference. 
B) The toothpaste did help after all. 
C) The toothpaste had a significant effect but you don't know in which way yet. 
D) The toothpaste made things worse.

Question 7

Suppose that a medical study found a statistically significant relationship between wearing gold jewelry and developing skin cancer.Suppose the study was based on a sample of 100,000 people and had a p-value of .049.How would you react to these results?

Accepted Answer

A) You feel these results are very convincing since the sample size was so large. 
B) You are impressed by the sample size but the p-value is too close to .05 to feel very convinced; the result is marginal. 
C) You are skeptical because the high sample size would lead to a small p-value even with a miniscule relationship, and thus gives misleading results. 
D) None of the above 
A) You feel these results are very convincing since the sample size was so large. 
B) You are impressed by the sample size but the p-value is too close to .05 to feel very convinced; the result is marginal. 
C) You are skeptical because the high sample size would lead to a small p-value even with a miniscule relationship, and thus gives misleading results. 
D) None of the above

Question 8

For Questions , use the following narrative
Narrative: Aspirin and polyps
A well-designed experiment by the Ohio State University Medical Center studied whether or not taking an aspirin a day would affect colon cancer patients' chances of getting subsequent colon polyps.In the study, 635 patients with colon cancer participated; 317 of them were randomly assigned to the aspirin group, and the other 318 patients were assigned to a placebo (non-aspirin) group.The results showed that 17% of the patients in the aspirin group developed subsequent polyps, compared to 27% of the patients in the non-aspirin group.The results are summarized in the table below.
  
-{Aspirin and polyps narrative} Compute the test statistic for the data.

Accepted Answer

The answer of For Questions , use the following narrative
Narrative:...

Question 9

Suppose you find a statistically significant relationship between two categorical variables (with no other supporting evidence available).When can such results correctly lead you conclude a cause and effect relationship?

Accepted Answer

A) Never. 
B) Only when the data were from a randomized experiment. 
C) Only when the data were from a random sample. 
D) Always; a statistically significant relationship wouldn't be significant unless there is a cause and effect relationship. 
A) Never. 
B) Only when the data were from a randomized experiment. 
C) Only when the data were from a random sample. 
D) Always; a statistically significant relationship wouldn't be significant unless there is a cause and effect relationship.

Question 10

A __________ test is a statistical procedure that is used to determine whether or not there is a relationship between two categorical variables.

Accepted Answer

The answer of A __________ test is a statistical procedure...

Question 11

Suppose a chi-square test statistic from a sample of size 1,000 is 38.2 with a p-value of .0001, so the relationship is statistically significant.If the sample size for this study had only been based on a sample size of 100 (but the percentages remained the same), what would the chi-square test statistic have been and what conclusion would have been drawn?

Accepted Answer

A) Chi-square = 38.2; p-value = .0001; the relationship is statistically significant. 
B) Chi-square = 3.82; p-value = .001; the relationship is statistically significant. 
C) Chi-square = 3.82; p-value = .052; the relationship is not statistically significant. 
D) None of the above. 
A) Chi-square = 38.2; p-value = .0001; the relationship is statistically significant. 
B) Chi-square = 3.82; p-value = .001; the relationship is statistically significant. 
C) Chi-square = 3.82; p-value = .052; the relationship is not statistically significant. 
D) None of the above.

Question 12

Suppose you want to investigate whether there is a relationship between the gender of college students and whether or not they wear hats in school.What would be your null hypothesis and your alternative hypothesis (in words)? Be sure to label clearly which hypothesis is which.

Accepted Answer

Null hypothesis: no relationsh

Question 13

Which of the following statements is true about chi-square tests?

Accepted Answer

A) A large chi-square test statistic results in a large p-value. 
B) A large p-value means that there is a good chance that the relationship is statistically significant. 
C) If the two variables are not related in the population, then less than 5% of the samples you could ever take would give you a test statistic of 3.84 or larger. 
D) All of the above. 
A) A large chi-square test statistic results in a large p-value. 
B) A large p-value means that there is a good chance that the relationship is statistically significant. 
C) If the two variables are not related in the population, then less than 5% of the samples you could ever take would give you a test statistic of 3.84 or larger. 
D) All of the above.

Question 14

The question researchers are really asking when they are looking for a relationship between two variables is whether or not that relationship is present in the __________.

Accepted Answer

The answer of The question researchers are really asking when...

Question 15

For Questions , use the following narrative
Narrative: Aspirin and polyps
A well-designed experiment by the Ohio State University Medical Center studied whether or not taking an aspirin a day would affect colon cancer patients' chances of getting subsequent colon polyps.In the study, 635 patients with colon cancer participated; 317 of them were randomly assigned to the aspirin group, and the other 318 patients were assigned to a placebo (non-aspirin) group.The results showed that 17% of the patients in the aspirin group developed subsequent polyps, compared to 27% of the patients in the non-aspirin group.The results are summarized in the table below.
  
-{Aspiring and polyps narrative} Write the expected counts in each of the four cells of the table in parentheses next to each of the observed counts.

Accepted Answer

Answers ar

Question 16

If two variables have a statistically significant relationship that does not necessarily mean the two variables have a relationship of practical importance.Describe how this could happen.

Accepted Answer

it depends on the sample size;

Question 17

A measure of how unlikely the test statistic would be if the null hypothesis were true is the __________.

Accepted Answer

The answer of A measure of how unlikely the test...

Question 18

For Questions , use the following narrative
Narrative: Teenage voting
Suppose you take a random sample of teenagers aged 18-19, and you find that 53% of the males in your sample are Democrats, and 54% of the females in your sample are Democrats, respectively.
-{Teenage voting narrative} Should these results be considered significant from a practical standpoint? Why or why not?

Accepted Answer

No; they are not sig

Question 19

A minor relationship in the population may achieve __________ significance but fail to achieve __________ significance if there are an extremely large number of observations.

Accepted Answer

(respectiv

Question 20

Which of the following statements is not true about the chi-square statistic for a 2 x 2 contingency table?

Accepted Answer

A) If it is greater than 3.84, reject the null hypothesis and accept the alternative hypothesis. 
B) If it is greater than 3.84, the relationship in the table is considered to be statistically significant. 
C) 95% of the tables for sample data from populations in which there is no relationship will have a chi-square statistic of 3.84 or greater. 
D) All of the above are true. 
A) If it is greater than 3.84, reject the null hypothesis and accept the alternative hypothesis. 
B) If it is greater than 3.84, the relationship in the table is considered to be statistically significant. 
C) 95% of the tables for sample data from populations in which there is no relationship will have a chi-square statistic of 3.84 or greater. 
D) All of the above are true.

Exam 13: Statistical Significance for 2 2 Tables

Which of these does not apply to a 'statistically significant' relationship between two categorical variables?

An interesting relationship in the population may fail to achieve __________ significance if there are too _____ observations.

Another name for the alternative hypothesis is the __________ hypothesis.

Suppose researchers say they 'failed to find a relationship' between two variables that they thought might have been related.What does this say to you, as an educated consumer of statistical information?

Suppose that a medical study found a statistically significant relationship between wearing gold jewelry and developing skin cancer.Suppose the study was based on a sample of 100,000 people and had a p-value of .049.How would you react to these results?

Suppose you find a statistically significant relationship between two categorical variables (with no other supporting evidence available).When can such results correctly lead you conclude a cause and effect relationship?

A __________ test is a statistical procedure that is used to determine whether or not there is a relationship between two categorical variables.

Suppose you want to investigate whether there is a relationship between the gender of college students and whether or not they wear hats in school.What would be your null hypothesis and your alternative hypothesis (in words)? Be sure to label clearly which hypothesis is which.

Which of the following statements is true about chi-square tests?

The question researchers are really asking when they are looking for a relationship between two variables is whether or not that relationship is present in the __________.

If two variables have a statistically significant relationship that does not necessarily mean the two variables have a relationship of practical importance.Describe how this could happen.

A measure of how unlikely the test statistic would be if the null hypothesis were true is the __________.

A minor relationship in the population may achieve __________ significance but fail to achieve __________ significance if there are an extremely large number of observations.

Which of the following statements is not true about the chi-square statistic for a 2 x 2 contingency table?

The Benefits and Risks of Using Statistics

Reading the News

Measurements, Mistakes, and Misunderstandings

How to Get a Good Sample

Experiments and Observational Studies

Getting the Big Picture

Summarizing and Displaying Measurement Data

Bell-Shaped Curves and Other Shapes

Plots, Graphs, and Pictures

Relationships Between Measurement Variables

Relationships Can Be Deceiving

Relationships Between Categorical Variables

Understanding Probability and Long-Term Expectations

Understanding Uncertainty Through Simulation

Psychological Influences on Personal Probability

When Intuition Differs From Relative Frequency

Understanding the Economic News

The Diversity of Samples From the Same Population

Estimating Proportions With Confidence

The Role of Confidence Intervals in Research

Rejecting Chancetesting Hypotheses in Research

Hypothesis Testingexamples and Case Studies

Significance, Importance, and Undetected Differences

Meta-Analysis: Resolving Inconsistencies Across Studies

Ethics in Statistical Studies

Putting What You Have Learned to the Test

Filters

An interesting relationship in the population may fail to achieve ______ significance if there are too _ observations.

A minor relationship in the population may achieve significance but fail to achieve significance if there are an extremely large number of observations.