Question 1

Suppose researchers would like to determine the proportion of Americans who own dogs. This would be a hypothesis testing problem.

Accepted Answer

Determining the proportion of Americans who own dogs is a descriptive statistics problem, not a hypothesis testing problem. Hypothesis testing is used to make inferences or draw conclusions about a population based on sample data, typically involving a comparison or a test of a specific hypothesis.

Question 2

Data from a poll of adults aged 30 to 40 in a small town led to the following estimates: Approximately 54% of adults aged 30 to 40 want to improve housing conditions and 72% of adults aged 30 to 40 consider the presence of a garage for a car as a very important attribute in a new house. What additional information about the survey would you need in order to decide if it is reasonable to generalize these estimates to the population of adults aged 30 to 40 of this small town?
A)In addition to the information provided, we would like to know if the subjects were randomly selected or not.
B)In addition to the information provided, we would like to know whether or not the subjects were randomly assigned to any experimental groups.
C)In addition to the information provided, we would like to know the total population of the city.
D)In addition to the information provided, we would like to know the number of adults aged 30 to 40.
E)In addition to the information provided, we would like to know the number of adults aged 30 to 40 who have a garage.

Accepted Answer

To generalize the survey results to the entire population, it is important to know if the sample was randomly selected, ensuring it is representative of the population.

Question 3

Suppose a researcher is collecting data about the amount of soda Americans consume in one day. If the researcher was to gather two separate representative samples from the population, differences may exist between these samples. These differences may be attributed to what?

Accepted Answer

Sampling variability

Question 4

List the five step process that should be used in a hypothesis testing problem.

Accepted Answer

The answer of List the five step process that should...

Question 5

Consider the following two statistical inference situations: I. A technician at a water-bottling facility wishes to test whether one of the filling machines is delivering less fluid per bottle than it is intended to deliver.
II) Another technician at this same facility wished to determine the number of milliliters of water being delivered per bottle for the filling machine in question.
Which of these inference situations are hypothesis testing problems?
A)I only
B)II only
C)both I and II
D)neither I nor II
E)Situations such as I and II are not suitable for statistical inference.

Accepted Answer

Situation I involves testing a specific claim (whether the machine is delivering less fluid than intended), which is a hypothesis testing problem. Situation II involves estimating a parameter (the number of milliliters delivered per bottle), which is an estimation problem, not hypothesis testing.

Question 6

In many areas of the U.S., honey bee populations have been devastated in recent years, and the cause is not yet well-understood. The general opinion amongst the beekeepers in a particular region is that the problem is intensifying, and a researcher sets out to settle this question by surveying the health of a large number of randomly-selected hives. Which of the following best describes this study?
A)hypothesis test with sample data
B)estimation study with sample data
C)hypothesis test with experimental data
D)estimation study with experimental data
E)All of these are good descriptions.

Accepted Answer

This study is a hypothesis test with sample data because the researcher is testing the general opinion (hypothesis) about the health of bee populations by examining a sample of hives.

Question 7

A technician wishes to examine the breaking pressures, in pounds per square inch, of three brands of adhesives. In this study, the adhesives are used to bond two identical squares of 1/2"-thick pieces of acrylic plastic face-on, and then the assembly is tensionally stressed until the bond fails.For each of the adhesive brands, the test is repeated for 50 trials. How many treatments are involved in this study?
A)3
B)1
C)50
D)150
E)2

Accepted Answer

The treatments refer to the different levels of the independent variable being tested, which in this case are the three brands of adhesives.

Question 8

The company conducted a study that investigated whether the classical music while waiting for the operator's response has an effect on the irritability of customers. In this study during the week customers were randomly assigned to either a control group (who listened to the usual beeps while waiting for the operator's response) or to an experimental group (who listened to the classical music while waiting for the operator's response). The operators during the conversation evaluated the level of irritability of the client as low, medium, and high. The company used these data to determine if there was evidence to support the claim that the mean level of irritability is higher for customers who listened to the classical music while waiting for the operator's response. For the study, answer the four key questions: 
A)Q: EstimationS: Experiment dataT: One variable, categoricalN: Two treatments
B)Q: Hypothesis testingS: Sample dataT: One variable, numericalN: One sample
C)Q: Hypothesis testing S: Experiment data
T: One variable, numerical
N: One sample
D)Q: Estimation S: Sample data
T: One variable, categorical
N: Two samples
E)Q: Hypothesis testing S: Experiment data
T: One variable, categorical
N: Two treatments

Accepted Answer

The answer of The company conducted a study that investigated...

Question 9

When selecting an appropriate method for data analysis, one important consideration is the number of and type of variables involved in the situation.

Accepted Answer

The number and type of variables involved are crucial in determining the most suitable statistical or analytical method for data analysis, as different methods are optimized for handling different types and quantities of data.

Question 10

The researchers conducted a survey of 350 adults that were selected in a way that would produce a representative sample of adult residents of the city. One question in the survey asked, "Do you plan to go abroad for a vacation this year?" The researchers hoped to learn about the proportion of adult residents of the city that planned to go abroad for a vacation this year. For the study, answer the four key questions:  ​
A)Q: EstimationS: Sample dataT: One variable, numericalN: One sample
B)Q: Hypothesis testingS: Sample dataT: One variable, categoricalN: One sample
C)Q: Hypothesis testing S: Experiment data
T: One variable, numerical
N: One sample
D)Q: Estimation S: Sample data
T: One variable, categorical
N: One sample
E)Q: Hypothesis testing S: Experiment data
T: One variable, categorical
N: Two treatments

Accepted Answer

The answer of The researchers conducted a survey of 350...

Question 11

Suppose a researcher is collecting data about the amount of soda Americans consume in one day. The researcher would like to determine if Americans consume over 12 ounces of soda per day on average. What question type (Q) is this: estimation or hypothesis testing?

Accepted Answer

The answer of Suppose a researcher is collecting data about...

Question 12

In many areas of the U.S., honey bee populations have been devastated in recent years, and the cause is not yet well-understood.A researcher surveys a large sample of honeybee colonies and rates each hive as "healthy" or "unhealthy". What best describes the type of data collected in this study?
A)univariate, numerical data
B)bivariate, numerical data
C)univariate, categorical data
D)bivariate, categorical data
E)none of these

Accepted Answer

The data collected is univariate because it involves only one variable (health status of the hive) and categorical because the hives are classified into categories (healthy or unhealthy) rather than measured numerically.

Question 13

For which of the following experimental questions would you be most interested in the population proportion instead of the population mean?
A)At this university, how many minutes a day do students exercise?
B)Do students at this university intend to seek work immediately after graduation?
C)Is the GPA of statistics students at this university higher than the national average?
D)What is the mean GPA of statistics students at this university?
E)Do students at this university score higher than the national average on the Graduate Record Examination (GRE)?

Accepted Answer

For question B, you're interested in whether students intend to seek work immediately after graduation, which is a categorical outcome (yes or no), making it suitable for analyzing a population proportion rather than a mean.

Question 14

List the five step process that should be used in an estimation problem.

Accepted Answer

The answer of List the five step process that should...

Question 15

Suppose a researcher is collecting data to compare the average amount of soda consumed daily by men and women. The researcher will ask participants to state the amount of soda they consumed on the previous day. The researcher would like to determine if differences exist in the amount of soda consumed between the genders. Is this an observational study or an experiment?

Accepted Answer

The answer of Suppose a researcher is collecting data to...

Question 16

For the described study below, select the answers for the following key questions:  A study was conducted to test an old adage that cats sleep more when the ambient temperature is higher. In the study, cats were isolated from distractions in areas of fixed temperature and were videotaped. The videotape footage was then reviewed to determine the percent of each 24-hour day spent asleep. Three large groups of randomly-selected cats were randomly assigned to one of three environmental temperatures.
A)Hypothesis; Experimental data; Univariate and numerical data; One treatment
B)Estimation; Sample data; Univariate and numerical; One treatment
C)Hypothesis; Experimental data; Bivariate and numerical data; Three treatments
D)Estimation; Sample data; Bivariate and categorical data; Three treatments
E)Estimation; Experimental data; Univariate and categorical; Three samples

Accepted Answer

The answer of For the described study below, select the...

Question 17

Suppose a researcher is collecting data to compare the average amount of soda consumed daily by men and women. The researcher will ask participants to state the amount of soda they consumed on the previous day. The researcher would like to determine if differences exist in the amount of soda consumed between the genders. What variable(s) are involved? Also, list the type of each variable.

Accepted Answer

The answer of Suppose a researcher is collecting data to...

Question 18

When selecting an appropriate method for data analysis, the only important consideration is the number of and type of variables involved in the situation.

Accepted Answer

Other important considerations include the research question or hypothesis, the level of measurement of the data, the distribution of the data, sample size, and assumptions of the statistical tests.

Question 19

Describe the difference between an estimation problem and a hypothesis testing problem.

Accepted Answer

The answer of Describe the difference between an estimation problem...

Quiz 7: An Overview of Statistical Inference - Learning From Data