Exam 2: An Introduction to Statistics

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 _____ of size n is a sample selected in such a way that every possible sample of size n has the same chance of being selected.

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:

In a study that seeks to evaluate the effect caffeine has on narcoleptics,40 narcoleptic patients are randomly selected to participate in the study.Fifteen of the patients are given high doses of caffeine,15 are given moderate doses,and 10 are given low doses over a period of 30 days.The variable in this study is the:

A clinical nurse supervisor (CNS)is designing an experiment that will evaluate the effectiveness of household pets in treating depression.Using computer software,she generates a list of 200 people.In the sampling process,every possible sample in the population of size 200 has the same chance of being selected.Is this a simple random sample?

A professor wishes to record information on some of his students for later use.He arrives to class early and samples the first five students that enter the room.Is this a simple random sample of size 5?

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)

Consider the population of the approximately 25,000 protein-coding genes in human DNA.Suppose each gene is assigned a number from 1 to 25,000 and computer software then used to randomly select 100 of these numbers,yielding a sample of 100 genes.Would this be a simple random sample?

We know that our population consists of equally likely numbers 1 to 6 inclusive (in other words,we know everything about the population).We wish to answer questions concerning a sample of two distinct numbers from this population.This is BEST described as a _____ problem.

Descriptive statistics may be BEST defined as:

In a _____ problem,we assume very little about a population.We use the information about a sample to answer questions concerning the population.

During July 2007,the National Association of College and Employers reported an increase in the average starting salaries of trades related to engineering.Offers to students awarded a bachelor's degree in chemical engineering rose 5.4% to an average of $59,361,and starting salaries for students awarded a bachelor's degree in computer engineering rose 4.8% to an average of $56,201.The numbers in this case are an example of:

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 2008 study examined the impact of the color red on how attractive men perceive a woman to be.The men were randomly divided into two groups and were asked to rate the attractiveness of women on a scale of 1 to 9.One group of men were shown pictures of women on a white background and the other group were shown the same pictures on a red background.This is BEST described as a(n)_____ study.

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 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.

The 2009 National Survey on Drug Use and Health selected a random sample of U.S.college students and asked them about illicit drug use.Roughly 23% of the students surveyed reported using illicit drugs in the past year.The population in this study is:

Inferential statistics may be BEST defined as:

In the mid-1990s a study was conducted to determine if arthroscopic surgery was an effective treatment for arthritis of the knee.Ten men were scheduled for surgery and each patient was anesthetized.But then the surgeon consulted a randomly generated code to determine whether to do the actual surgery,or to perform a "sham" surgery (make three small incisions in the knee,stitch the patient up,and leave a small scar).This is BEST described as a(n)_____ study.

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: