Question 1

Nuclear power plants must discharge the excess heat generated in the nuclear process to the environment.Some plants exhaust this heat to nearby water sources.There is concern that this "thermal pollution" has an adverse effect on aquatic life near the plant.The EPA catches 100 fish from the discharge pond of a particular power plant.They track the growth rates and life span of these fish and compare them to fish from similar streams whose temperatures are not affected by the plant's thermal effluent.The sample in this experiment is:
A) all nuclear power plants.
B) the selected nuclear power plant.
C) all fish in the discharge path.
D) the 100 fish caught by the EPA.

Accepted Answer

The sample in this experiment is the 100 fish caught by the EPA from the discharge pond, as they are the specific subjects being studied and compared to fish from unaffected streams.

Question 2

In a(n)_____ problem,certain characteristics of a population are assumed known.We then answer questions concerning a sample from that population. 
A) statistical inference
B) inferential statistical
C) probability
D) statistics

Accepted Answer

C

Question 3

In a(n)_____,we investigate the effects of certain conditions on individuals or objects in the sample.
A) statistical setting
B) observational study
C) experimental study
D) population

Accepted Answer

In an experimental study, researchers manipulate certain conditions or variables and observe their effects on individuals or objects in the sample. This allows for the establishment of cause-and-effect relationships between variables. In contrast, observational studies simply observe and record data without manipulating any variables. Statistical setting refers to the broader context in which statistical analysis is applied, and population refers to the entire group of individuals or objects that the sample is drawn from.

Question 4

A _____ sample has characteristics similar to those of the entire population and therefore can be used to draw a conclusion about the (general)population.
A) general
B) descriptive
C) statistical
D) representative

Accepted Answer

A representative sample accurately reflects the characteristics of the population, making it suitable for drawing conclusions about the population as a whole. A general sample is too broad and undefined, a descriptive sample only describes the variables and does not indicate if it is representative or not, and a statistical sample only focuses on the numbers and not the representativeness.

Question 5

The effect of different lighting levels on productivity is evaluated using a designed experiment.Two hundred office workers who have the same basic job assignments are randomly selected to participate.Each worker is randomly assigned a different lighting level at his or her desk.Ambient (background)lighting is held constant for all workers.A benchmark of productivity is recorded for each worker.In this study,the sample is best described as:
A) 200 office workers.
B) the different lighting levels.
C) the amount of productivity.
D) all office workers with similar job assignments.

Accepted Answer

The sample in this study is the 200 office workers who have the same basic job assignments and are randomly selected to participate in the experiment. The other variables, such as the lighting levels and productivity, are the factors being manipulated and measured within the sample. Therefore, the best choice is A) 200 office workers.

Question 6

Mice are given a protein injection that is designed to promote physical growth.Fifty mice are randomly selected for evaluation in the study.Some of the mice are injected with high levels of the protein,some with low levels,and a third group receives a placebo (saline injection).The amount of growth of the mice is recorded and compared.In this study,the variable is best described as:
A) 50 randomly selected mice.
B) all mice that receive a protein injection.
C) the type of protein used.
D) the amount of protein injected.

Accepted Answer

The variable in this study is the amount of protein injected, as this is what is being manipulated to observe its effect on physical growth. The other options describe features of the sample or the experiment design, but they do not represent the variable being studied.

Question 7

In September of 2000 the United Nations adopted an initiative known as the UN Millennium Declaration.The goal was to take active steps in eliminating poverty,HIV/AIDS,hunger,and other global issues adversely affecting humanity by 2015.The UN consistently tracks each country's progress by recording data on numerous markers that provide an indication of compliance with these "Millennium Development Goals." The data for each country is summarized by year in tabular format.The organization of this raw data into a more user-friendly table format is an example of: (See: http://www.un.org/millenniumgoals/stats.shtml)
A) inferential statistics.
B) the scientific method.
C) descriptive statistics.
D) population statistics.

Accepted Answer

The organization of raw data into a more user-friendly table format is an example of descriptive statistics, which involves the numerical and graphical summaries of data in order to describe or summarize a particular phenomenon. Inferential statistics involve making conclusions and predictions about a larger population based on a sample of data, and the scientific method involves a systematic approach to scientific inquiry. Population statistics refers to the characteristics of a population as a whole, rather than just a sample.

Question 8

Inferential statistics may be BEST defined as:
A) techniques and methods used to analyze a small,specific set of data in order to draw a conclusion about a large,more general collection of data.
B) graphical and numerical methods used to describe,organize,and summarize a statistically valid conclusion.
C) graphical and numerical methods used to describe,organize,and summarize data.
D) techniques and methods used to analyze a small data set to make inference concerning its accuracy.

Accepted Answer

Inferential statistics is all about using a small, specific set of data to draw conclusions about a much larger population. This involves techniques and methods such as hypothesis testing, confidence intervals, and regression analysis. Option A is the most accurate definition of this concept. Option B describes descriptive statistics, while option D is not a complete definition of inferential statistics.

Question 9

Two thousand people are surveyed and asked to indicate on a scale of 1 to 5 their preference for a particular brand of liquid dishwashing detergent.The responses are summarized using a bar graph that displays the total counts of each response (1 to 5).This is an example of:
A) inferential statistics.
B) simple random sampling.
C) pictorial statistics.
D) descriptive statistics.

Accepted Answer

This is an example of descriptive statistics because it summarizes and describes the data collected from the sample of 2000 people. There is no inference or generalization made about the population beyond the sample surveyed.

Question 10

Descriptive statistics may be BEST defined as:
A) techniques and methods used to analyze a small,specific set of data in order to draw a conclusion about a large,more general collection of data.
B) graphical and numerical methods used to describe,organize,and summarize a statistically valid conclusion.
C) graphical and numerical methods used to describe,organize,and summarize data.
D) techniques and methods used to analyze a small data set in order to describe its usefulness in making general statements about a population.

Accepted Answer

Descriptive statistics are used to summarize and describe data, and can include graphical and numerical methods. They are not necessarily focused on making conclusions about larger populations, but rather on understanding and characterizing the specific data at hand.

Question 11

Electrical engineers are attempting to maximize the efficiency of an experimental battery cell.They wish to determine the optimum charge rate that will provide maximum battery capacity.They sample 50 cells and randomly assign five different charge rates to the sample (10 cells for each charge rate).All cells are then discharged at the same rate with total capacity recorded in amp-hours.The variable in this experiment is:
A) all experimental battery cells.
B) the different charge rates.
C) the total capacity recorded in amp-hours.
D) the 50 sampled cells.

Accepted Answer

The variable in this experiment is the different charge rates as they are being manipulated by the researchers to determine the optimum charge rate for maximum battery capacity. The other options are not the variable as they are either the population of cells being sampled or the outcome being measured.

Question 12

A sample of five people is analyzed to make a general statement concerning the population from which the people were sampled.This is an example of using:
A) inferential statistics.
B) descriptive statistics.
C) simple random sampling analysis.
D) inferential random sampling analysis.

Accepted Answer

Inferential statistics is used to make generalizations about the population based on a sample. In this case, the sample of five people is being analyzed to make a general statement about the population. Therefore, inferential statistics is being used. Descriptive statistics, on the other hand, would be used to summarize and describe the characteristics of the sample itself, rather than making predictions about the population. Simple random sampling analysis and inferential random sampling analysis are not applicable in this context as they refer to the methods used to obtain the sample, rather than the analysis of the sample.

Question 13

In 2004,the San Francisco police began using DNA evidence in unsolved homicides.The crime lab found evidence that suggested John Puckett was a DNA match for a crime committed three decades earlier,based on 5¹/₂ genetic locations.Usually 13 genetic markers are used to distinguish between two different people.Jurors were told that the chance of randomly finding the defendant's DNA profile at the crime scene was 1 in 1.1 million.The jurors found the DNA evidence compelling and convicted Puckett of first-degree murder.This conclusion is an example of: A) relative frequency and probability. B) summary statistics. C) probability and odds. D) statistical likelihood and inference.

Accepted Answer

The conclusion is based on statistical likelihood and inference, as the jurors used the probability of the DNA match to infer Puckett's guilt.

Question 14

A random sample of 10 cars is analyzed to evaluate the effect of installing a computer chip modification on a vehicle's horsepower.Based on the sample,researchers conclude that there is a significant increase in vehicle horsepower associated with the computer chip.This is an example of:
A) inferential statistics.
B) the scientific method.
C) descriptive statistics.
D) population statistics.

Accepted Answer

Inferential statistics involves drawing conclusions and making inferences about a population based on a sample. In this case, the researchers have used a sample of 10 cars to make a conclusion about the effect of the computer chip modification on horsepower for a larger population of cars. Therefore, this is an example of inferential statistics.

Question 15

A group of 20 monitor lizards is observed over the course of the lizards' life spans.The total food consumption of each lizard is recorded and displayed on a bar graph.This presentation of raw information in a more user-friendly format is an example of:
A) inferential statistics.
B) simple random sampling.
C) pictorial statistics.
D) descriptive statistics.

Accepted Answer

Descriptive statistics involves organizing, summarizing and displaying data in a way that is easy to understand. This is exemplified in the scenario where the food consumption of each lizard is displayed on a bar graph, making it easier to interpret the data. Inferential statistics involves making predictions or inferences about a larger population based on sample data, while simple random sampling involves randomly selecting a subset of individuals from a larger population. Pictorial statistics, also known as graphical representations, are used to visually convey data.

Question 16

Electrical engineers are attempting to maximize the efficiency of an experimental battery cell.They wish to determine the optimum charge rate that will provide maximum battery capacity.They sample 50 cells and randomly assign five different charge rates to the sample (10 cells for each charge rate).All cells are then discharged at the same rate with total battery capacity for each cell recorded in amp-hours.This is an example of a(n)_____ study.
A) simple random
B) experimental
C) observational
D) probability

Accepted Answer

This is an experimental study where the electrical engineers are intentionally manipulating the charge rate to determine its effect on battery capacity. The random assignment of charge rates to different cells helps to control for potential confounding variables and increase internal validity. The sampling of 50 cells also suggests that the study has a sufficient sample size to yield meaningful results.

Question 17

A behavioral scientist wishes to know more about the walking habits of university students across a particular campus sidewalk.She positions herself out of sight of the students who are walking and records the time required for several of them to pass between two fixed points along the sidewalk.This study is best described as a(n)_____ study.
A) observational
B) educational
C) experimental
D) scientific

Accepted Answer

This study is observing and recording the walking habits of university students, without manipulating or interfering with their behavior. Therefore, it is an observational study.

Question 18

In a(n)_____,we merely observe the response for a specific variable for each individual or object.
A) statistical setting
B) observational study
C) experimental study
D) population

Accepted Answer

An observational study involves merely observing the response for a specific variable for each individual or object without any intervention or manipulation of the variable. In contrast, experimental studies involve manipulating the variable and observing the effect on the outcome. A statistical setting refers to the context in which statistical methods and techniques are used, and population refers to the group of individuals or objects that the observations are drawn from.

Question 19

A psychologist wishes to test a behavioral modification therapy that is claimed to improve the behavior of pre-teen autistic children.She randomly selects 20 pre-teen autistic children and exposes half of the group to the behavioral modification therapy while the other half continue with their standard treatment regimen.A standardized behavioral test is administered to each child both before and after his/her respective treatment.The population in this experiment is:
A) all pre-teen autistic children.
B) the behavioral modification therapy.
C) the standardized behavioral test scores.
D) the 20 selected pre-teen autistic children.

Accepted Answer

The population in this experiment is all pre-teen autistic children, as the psychologist wishes to test a behavioral modification therapy on this group. The selected 20 pre-teen autistic children are a sample from this population. The behavioral modification therapy and the standardized behavioral test scores are not the population, but rather the variables being studied.

Question 20

In a study of crop rotation techniques,agricultural researchers are interested in making general statements concerning the effectiveness of a given technique for all corn fields in the state of Kansas.Using a cluster technique,they randomly choose 30 farms from across the state for their study.Some of the chosen farms are randomly selected to use the rotation technique whereas others are not.In this study,the population is best described as:
A) 30 farms chosen from across the state.
B) all corn fields in the state of Kansas.
C) the effectiveness of crop rotation.
D) whether the rotation technique was used or not.

Accepted Answer

The population of interest in this study is all corn fields in the state of Kansas, as the researchers aim to make general statements about the effectiveness of crop rotation for these fields. The 30 farms chosen from across the state are a sample of this population. The use of the cluster technique allows for random sampling across different regions of the state, which helps to ensure the sample is representative of the population. The choice of whether or not to use the rotation technique is a variable being tested in the study, but it does not define the population.

Quiz 2: An Introduction to Statistics

In a(n) _____ problem,certain characteristics of a population are assumed known.We then answer questions concerning a sample from that population.

In a(n) _____,we investigate the effects of certain conditions on individuals or objects in the sample.

A _____ sample has characteristics similar to those of the entire population and therefore can be used to draw a conclusion about the (general) population.

Inferential statistics may be BEST defined as:

Two thousand people are surveyed and asked to indicate on a scale of 1 to 5 their preference for a particular brand of liquid dishwashing detergent.The responses are summarized using a bar graph that displays the total counts of each response (1 to 5) .This is an example of:

Descriptive statistics may be BEST defined as:

A sample of five people is analyzed to make a general statement concerning the population from which the people were sampled.This is an example of using:

A random sample of 10 cars is analyzed to evaluate the effect of installing a computer chip modification on a vehicle's horsepower.Based on the sample,researchers conclude that there is a significant increase in vehicle horsepower associated with the computer chip.This is an example of:

A group of 20 monitor lizards is observed over the course of the lizards' life spans.The total food consumption of each lizard is recorded and displayed on a bar graph.This presentation of raw information in a more user-friendly format is an example of:

In a(n) _____,we merely observe the response for a specific variable for each individual or object.