Module 1

The average GPA of a​ university's graduating class Statistic Parameter

parameter

The average height of horse jockeys Statistic Parameter

parameter

A report stated that ​"62​% of people between the ages of 18 and 29 favor raising the minimum wage.​" The percentage of 62​% was computed from sample data. Complete parts​ (a) through​ (d) below. a. Identify the population under consideration. The population is all people between the ages of 18 and 29. b. Identify the sample under consideration. The sample is all people between the ages of 18 and 29 who were surveyed. c. Is the statement in quotes descriptive or​ inferential? Choose the correct answer below. A. The statement is​ descriptive, since it summarizes information about the sample. B. The statement is​ inferential, since it draws a conclusion about the population based on a sample. Your answer is correct.C. The statement is​ inferential, since it draws a conclusion about the population based on the percentage who favor raising the minimum wage.

population all people between the ages of 18 and 29 The sample is all people between the ages of 18 and 29 who were surveyed. The statement is​ inferential, since it draws a conclusion about the population based on a sample.

The average age of 25 congressional members who were selected at random from all U.S. Congressmen Parameter Statistic

statistic

The average weekly amount spent on groceries by a family of four based on a random sample of 100 families Statistic Parameter

statistic

The information we gather with experiments and with surveys is collectively called data. False True

true

The job placement center at your school surveys all graduating seniors at the school. Their report about the survey provides numerical summaries such as the average starting salary and the percentage of students earning more than ​$40 comma 000 a year. a. Are these​ descriptive, or​ inferential, statistical​ analyses? Explain. b. Are these numerical summaries better characterized as statistics or as​ parameters? a. Are the statistical analyses descriptive or inferential​ statistics? A. ​Descriptive, because they make predictions about the population. B. ​Inferential, because they summarize the data collected. C. ​Inferential, because they make predictions about the population. D. ​Descriptive, because they summarize the data collected. Are these numerical summaries better characterized as statistics or as​ parameters? A. ​Statistics, because the analyses summarize data on a population. B. ​Parameters, because the analyses summarize data on a sample. C. Parameters​, because the analyses summarize data on a population. This is the correct answer. D. Statistics​, because the analyses summarize data on a sample.

​Descriptive, because they summarize the data collected Parameters​, because the analyses summarize data on a population.

The statement​ "A meteorologist constructs a graph showing the total precipitation in​ Phoenix, Arizona in each of the months of a given​ year" refers to which aspect of a statistical​ study? Design Inference Description

Description

In​ sampling, explain why obtaining a representative sample is important. Why is obtaining a representative sample​ important? A. The sample must be representative in order to establish causation rather than only reveal association. B. The sample must be representative in order to be considered a simple random sample. C. The sample must be representative in order to be used as part of a designed experiment rather than an observational study. D. The sample must be representative in order to use inferential statistics to draw conclusions about the entire population

The sample must be representative in order to use inferential statistics to draw conclusions about the entire population

. What is the aspect of this study that pertains to​ design? A. Selecting the individuals for the​ test, while assigning each individual to either take a regular aspirin or a placebo. B. Arriving at the conclusion that taking a regular aspirin reduces cholesterol. C. Deciding to use a placebo in the study. D. Summarizing the results using percentages.

A

A study attempted to estimate the proportion of Florida residents who were willing to spend more tax dollars on protecting the Florida beaches from environmental disasters. ​Twenty-four hundred Florida residents were surveyed. Which of the following is the population of interest in the​ study? A. all Florida residents B. all residents of the United States C. all Florida residents who were willing to spend more tax dollars on protecting the beaches from environmental disasters. D. all Florida residents who lived along the beaches E. the 2400 Florida residents surveyed

A

In a clinical​ trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one dash month ​period, the first group received a low dosage of an experimental​ drug, the second group received a high dosage of the​ drug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. Identify the experimental units. A. The participants in the experiment Your answer is correct.B. The diastolic blood pressures of the participants C. The three different groups D. The unit used to measure blood pressure E. The treatment​ (i.e., placebo, low dosage of​ drug, or high dosage of​ drug)

A

In a​ survey, 71% of 1052 adults polled nationwide answered​ "Yes" to the question​ "Do you believe the theory that increased carbon dioxide and other gases released into the atmosphere​ will, if​ unchecked, lead to global warming and an increase in average​ temperatures?" The predicted proportion of all American adults who would respond​ "Yes" to the question is an example of​ what? A parameter A statistic Random sampling The sample The population

A Parameter

A survey of American adults asks​ "Would you like to see more or less government spending on natural​ disasters?" Of the 1496​ respondents, 723 responded​ "more" or​ "much more". The proportion of respondents who responded​ "more" or​ "much more" is an example of​ what?

A statistic

In a​ survey, 71% of 1052 adults polled answered​ "Yes" to the question​ "Do you believe the theory that increased carbon dioxide and other gases released into the atmosphere​ will, if​ unchecked, lead to global warming and an increase in average​ temperatures?" The​ 71% responding​ "Yes" to the question is an example of​ what? A parameter A statistic Your answer is correct. The sample The population Random sampling

A statistic

A survey of American adults asks​ "Would you like to see more or less government spending on natural​ disasters?" Of the 1496​ respondents, 723 responded​ "more" or​ "much more". What does the population of interest consist​ of? A. All American adults .B. The proportion of respondents who responded​ "more" or​ "much more" C. The 1496 respondents D. The 723 respondents who responded​ "more" or​ "much more" E. The proportion of American adults estimated to respond​ "more" or​ "much more"

A. all

What is the aspect of this study that pertains to​ description? A. Flipping a coin to determine if the individual would take a regular aspirin or a placebo. B. Concluding that taking a regular aspirin reduces cholesterol. C. Stating the summarizing percentages of the 20 comma 000 individuals. Dividing the 20 comma 000 individuals into 2 separate groups. c. What is the aspect of this study that pertains to​ inference? A. Stating the percentages of individuals who had high cholesterol in each group of the 20 comma 000 individuals. B. Measuring the occurrence of high cholesterol among the individuals. C. Assigning each individual to two separate groups. D. Concluding that taking a regular aspirin reduces cholesterol.

C. Stating the summarizing percentages of the 20 comma 000 individuals.

To avoid working​ late, a quality control analyst simply inspects the first 100 items produced in a day. Cluster random sample Convenience sample Your answer is correct. Stratified random sample Simple random sample Matched pair sample

Convenience sample

In a survey of students at a certain​ college, 677 students were asked whether they believed in life after death and whether they believed in reincarnation. The results are summarized in the accompanying table. When asked whether or not they believed in life after​ death, what percentage of those surveyed said​ yes, definitely;​ yes, probably;​ no, probably​ not; and​ no, definitely​ not? LOADING... Click the icon to view the frequency distribution. A. ​9.5%, 37.7%,​ 19.9%, 31.0% B. ​255%, 210%,​ 130%, 82% C. ​9.5%, 19.9%,​ 43.0%, 27.6% D. ​37.7%, 31.0%,​ 19.2%, 12.1%

D

A poll of about 1250 people between the ages of 30 and 49 asked​ "How concerned are you about the problem of natural disasters​?" The possible responses were very​ concerned, somewhat​ concerned, not very​ concerned, and​ haven't heard about it. The poll reported percentages left parenthesis 42 comma 31 comma 21 comma 5 right parenthesis in these categories. Complete parts a and b below. a. Identify the sample and the population. Choose the correct answer below. A. The sample is the set of 1250 people that were​ polled, while the population is the set of all people. B. The sample is the set of all people between the ages of 30 and 49 who are concerned about natural disasters​, while the population is the set of all people between the ages of 30 and 49. C. The sample is the set of people between the ages of 30 and 49​, while the population is the set of all people. D. The sample is the set of 1250 people that were​ polled, while the population is the set of all people between the ages of 30 and 49 Are the percentages quoted statistics or​ parameters? Why? A. The percentages quoted are parameters because they can be used to make decisions or predictions about a population. B. The percentages quoted are statistics because they represent all of the possible responses to the poll question. C. The percentages quoted are parameters because they are a numerical summary of the entire population. D. The percentages quoted are statistics because they are a numerical summary of a sample taken from a population.

D. The sample is the set of 1250 people that were​ polled, while the population is the set of all people between the ages of 30 and 49 D. The percentages quoted are statistics because they are a numerical summary of a sample taken from a population.

Identify the study as observational or experimental. Twenty volunteers who suffer from sleep apnea are randomly divided in half so that ten receive a new medication to reduce snoring while the remaining ten receive a placebo that looks like the medication. The volunteers are unaware of which group they are in and are observed at a sleep clinic overnight. Experimental .Observational

Experimental

Descriptive statistics refers to methods of making decisions or predictions about a​ population, based on data obtained from a sample of that​ population; while inferential statistics refers to methods for summarizing the data. True False

False

The statement​ "Based on previous​ clients, a marriage counselor concludes that the majority of marriages that begin with cohabitation before marriage will result in​ divorce" refers to which aspect of a statistical​ study? Inference Description Design

Inference

A magazine publisher mails a survey to every subscriber asking about the quality of its subscription service. From which of the following is this study most likely to​ suffer? Nonresponse bias Your answer is correct. Sampling bias Undercoverage Both nonresponse bias and undercoverage Both undercoverage and sampling bias

Nonresponse bias

Identify the study as observational or experimental. At one​ hospital, 674 women were diagnosed with breast cancer. Five years​ later, 88% of the Caucasian women and​ 83% of the African American women were still alive. Experimental Observational

Observational

A study was completed that provides a comprehensive body of data on the labor​ force, unemployment,​ wealth, poverty, and so on. Data examined 50 comma 000 ​households, each consisting of at least one related person under the age of 18. The report indicated that 17​% of white​ households, 36.6​% of black​ households, and 13.1​% of Asian households had annual incomes below the poverty line. Based on these​ results, the study authors concluded that the percentage of all such black households with annual incomes below the poverty line is between 34.2​% and 39​%. Complete parts a and b below. a. What is the aspect of this study that pertains to​ description? A. Percentages of the 50 comma 000 households who had incomes below the poverty level This is the correct answer.B. Dividing the households into 3 separate groups C. Predicting that the percentage of all black households that had income below the poverty level is between 34.2​% and 39​% D. Stating that the study covers information regarding data on the labor​ force, unemployment,​ wealth, poverty, and so on b. What is the aspect of this study that pertains to​ inference? A. Predicting that the percentage of all black households that had income below the poverty level is between 34.2​% and 39​%. This is the correct answer. B. Stating that the study covers information regarding data on the labor​ force, unemployment,​ wealth, poverty, and so on

Percentages of the 50 comma 000 households who had incomes below the poverty level

Classify the data as either qualitative or quantitative. For the year​ 2006, a large record company reported the sales figures to the right for various music media. What kind of data is provided by the information in the first​ column? font size decreased by 1 Start 9 By 2 Table 1st Row 1st Column Media 2nd Column Sales left parenthesis $ millions right parenthesis 2nd Row 1st Column CD 2nd Column 1477.3 3rd Row 1st Column CDsingle 2nd Column 1.8 4st Row 1st Column MP 3 2nd Column 65.9 5st Row 1st Column Vinyl 2nd Column 2.6 6st Row 1st Column Music video 2nd Column 531.4 7st Row 1st Column Mini Disc 2nd Column 0.3 8st Row 1st Column DVD 2nd Column 108.2 9st Row 1st Column Cassette 2nd Column 3.4 EndTable Qualitative Your answer is correct. Quantitative

Qualitative

The name of each contestant is written on a separate​ card, the cards are placed in a​ bag, and three names are picked from the bag. Matched pair sample Convenience sample Cluster random sample Simple random sample Your answer is correct. Stratified random sample

Simple random sample

a. Distinguish between description and inference as reasons for using statistics. b. Suppose you have data for a​ population, such as obtained in a census. Explain why descriptive statistics are​ helpful, but inferential statistics are not needed. a. Which statement below best distinguishes description from​ inference? A. Statistical inference provides useful summaries of the​ data, while description helps make predictions and decide whether observed patterns are meaningful. B. Statistical description provides useful summaries of the​ data, while inference helps make predictions and decide whether observed patterns are meaningful. .C. Statistical description provides useful summaries of data for a​ sample, while inference provides useful summaries of data for a population. D. Statistical inference provides useful summaries of data for a​ sample, while description provides useful summaries of data for a population. b. Why are descriptive statistics​ helpful, but inferential statistics not​ needed? A. Descriptive statistics can summarize the large amount of raw​ data, but since everything is known for the​ population, there is nothing to infer. .B. Descriptive statistics can help make predictions about the​ population, but the amount of data in the inferential statistics is too large to be helpful. C. Descriptive statistics can summarize the large amount of raw​ data, but the amount of data in the inferential statistics is too large to be helpful. D. Descriptive statistics can help make predictions about the​ population, so there is nothing to infer. Question is complete.

Statistical inference provides useful summaries of the​ data, while description helps make predictions and decide whether observed patterns are meaningful. Why are descriptive statistics​ helpful, but inferential statistics not​ needed? A. Descriptive statistics can summarize the large amount of raw​ data, but since everything is known for the​ population, there is nothing to infer.

A market researcher selects 500 drivers under 30 years of age and 500 drivers who are 30 years of age and older. Convenience sample Cluster random sample Simple random sample Matched pair sample Stratified random sample

Stratified random sample

Determine whether the experiment is blind​, double blind​, or neither. A researcher wants to examine the effects of fertilizer and sunlight on tomato yield. To conduct her​ experiment, she randomly assigns 30 plants to receive 3 hours of sunlight a day and another 30 to receive 8 hours of sunlight a day. Within each of these​ groups, the plants are further divided so that 10 receive no​ fertilizer, 10 are fertilized every other week and 10 are fertilized twice a week. In all other respects the plants are treated identically. Each plant is grown to maturity and the total yield of each plant is recorded. The person measuring the yields does not know which plants received which treatments. Subjects are blinded Your answer is correct. Investigators are blinded Double blind Neither

Subjects are blinded

Is the percentage provided a descriptive statistic or an inferential​ statistic? Explain your answer. A. The percentage is an inferential​ statistic, since it draws a conclusion about how much of the population favors breaking up the megabanks. B. The percentage is an inferential​ statistic, since it draws a conclusion about how much of the sample favors breaking up the megabanks. C. The percentage is a descriptive​ statistic, since it summarizes information about how much of the population favors breaking up the megabanks. D. The percentage is a descriptive​ statistic, since it summarizes information about how much of the sample favors breaking up the megabanks.

The percentage is a descriptive​ statistic, since it summarizes information about how much of the sample favors breaking up the megabanks.

Identify the population and sample for this study. Choose the correct answer below. A. The population is the 1000 adults surveyed. The sample is those adults who favored breaking up the megabanks. B. The population is all adults in the country who favored breaking up the megabanks. The sample is the 1000 adults surveyed. C. The population is all adults in the country. The sample is the 1000 adults surveyed. Your answer is correct.D. The population is all adults in the country. The sample is those adults who favored breaking up the megabanks.

The population is all adults in the country. The sample is the 1000 adults surveyed

One year a survey asked a group of people from a certain country the following​ question, "How many children do you have question mark " Of the 848 people who​ responded, 5​% reported having only 1 child. Identify​ (a) the​ sample, (b) the​ population, and​ (c) the statistic reported. ​(a) What is the sample for this​ survey? A. The sample is the people in the particular country who did not respond. B. The sample is the 5​% who reported having only one child. C. The sample is the public in the particular country. D. The sample is the 848 people who responded. Your answer is correct. ​(b) What is the population for this​ survey? A. The population is all of the people in the world. B. The population is the 5​% who reported having only 1 child. C. The population is the public in the particular country.

The sample is the 848 people who responded. C. The population is the public in the particular country.

Classify the study as either descriptive or inferential. Explain your answer. A company provides an online database that provides real estate information for homes that are for rent or sale in a certain country. It also presents statistics on recently sold homes. The following table gives various information on all homes sold in several different cities in the country for one month. City Price per square foot Sale to list price ratio ​% foreclosure​ re-sales A ​$155 0.971 12.63​% B ​$435 0.988 2.84​% C ​$641 1.038 6.76​% D ​$nbsp 80 1.000 19.67​% E ​$103 0.979 18.26​% Is the study descriptive or​ inferential? A. The study is​ inferential, because the table is a summary of the data that was collected. B. The study is​ inferential, because the data was used to estimate averages for the population in each of the cities. C. The study is​ descriptive, because the data was used to estimate averages for the population in each of the cities. D. The study is​ descriptive, because the table is a summary of the data that was collected.

The study is​ descriptive, because the table is a summary of the data that was collected.

A survey of American adults asks​ "Would you like to see more or less government spending on natural​ disasters?" Of the 1496​ respondents, 723 responded​ "more" or​ "much more". What does the sample consist​ of? A. The 723 respondents who responded​ "more" or​ "much more" B. The proportion of respondents who responded​ "more" or​ "much more" C. The 1496 respondents .D. The proportion of American adults estimated to respond​ "more" or​ "much more" E. All American adults

c

Classify the data as either discrete or continuous. The number of freshmen entering college in a certain year is 621. Discrete Your answer is correct. Continuous

discrete

Determine whether the experiment is blind​, double blind​, or neither. 780 men suffering from high blood pressure were randomly assigned to one of two groups. Over a​ four-month period, the first group received an experimental drug and the second group received a placebo. A larger decrease in diastolic blood pressure was observed for those who received the drug. The patients did not know whether they were receiving the drug or the placebo. Neither the technicians administering the treatments nor the physicians evaluating the results knew which participants had received the drug and which the placebo. Subjects are blinded Investigators are blinded Double blind Your answer is correct. Neither

double blind

A lobbyist for a major airspace firm wants to get the opinion of state legislators on an issue of importance to his industry. The lobbyist contacts 10 state legislators at a restaurant during a lunch break and each one is polled about the issue. This technique produces a random sample. True False

false

The owners of a coffee shop conducted a taste test to determine whether its customers preferred a new coffee brand to the current one sold by the shop. Customers who were willing to participate were given small samples of each of the two brands in random order and were asked to select which one they preferred without knowing the brand. Of the 100 participating​ customers, 90% chose the new brand. Based on these​ results, the owners determined that a majority of their customers preferred the new brand and switched their coffee supplier. Predicting the preference of all of the coffee shop customers based on the taste test results refers to which aspect of​ statistics? Investigation Design Description Inference Your answer is correct. None of these

inference

From past​ figures, it is predicted that​ 39% of the registered voters in California will vote in the June primary. Which type of statistics does this statement​ reflect, inferential statistics or descriptive​ statistics? Descriptive statistics Inferential statistics

inferential