Exam 2: An Introduction to Statistics and Statistical Inference

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

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 major pharmaceutical company is conducting clinical trials on a new drug it wants to bring to market.The company surveys 2000 people who have the particular condition that the drug is designed to treat.A portion of the people surveyed receive a high dose of the drug, a portion of the people surveyed receive a medium dose of the drug, and the remaining portion of the people surveyed receive a placebo (sugar pill).The variable in this experiment is:

In September 2000, the United Nations adopted an initiative known as the UN Millennium Declaration.Its intention was to take active steps toward 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 the country's compliance with these "Millennium Development Goals." The data for each country are summarized by year in tabular format (see http://www.un.org/millenniumgoals/stats.shtml).The organization of these raw data into a more user-friendly table format is an example of:

An experiment that forces rats to take a particular direction at a junction in a maze and then observes the differences in times for the rats that went left and rats that went right is a(n) _________________ study.

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

Ten apples are taken off the top of a truckload of apples, and the amount of bruising on those apples is measured to estimate how much bruising is present, on average, in the whole truckload.Is this a simple random sample?

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

Two thousand people are surveyed and asked to indicate, using 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).The graph is used to predict the consumer response to a new detergent product.This is an example of:

During July 2007, the National Association of Colleges 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 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 using a scale of 1 to 9.One group of men was shown pictures of women on a white background, whereas the other group was shown the same pictures on a red background.This is best described as a(n) _________________ study.

An artist mass-produces sculptures that are claimed to be 99% identical.To test this claim, 50 of the artist's sculptures are selected from a local retail store.The sculptures are analyzed for any eccentricities.The population in this study is:

Descriptive statistics is best defined as:

The 2009 National Survey on Drug Use and Health selected a random sample of U.S.college students and asked them if they had ever used illicit drugs.Approximately 23% of the students surveyed reported using illicit drugs in the past year.The variable in this study is:

An experiment that simply records the direction a rat turns at a particular junction in a maze is a(n) _________________ study.

Electrical engineers are attempting to maximize the efficiency of an experimental battery cell.They wish to determine the optimum charge rate that will provide the 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 the total battery capacity being recorded in amp-hours.The variable controlled in this experiment is:

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 who enter the room.Is this a simple random sample of size 5?

State highway safety experts claim that the recent increase in highway fatalities involving tractor trailers is a result of truckers receiving insufficient rest.They randomly sample 200 truckers who are making interstate deliveries and record the total amount of nondriving time they have had over the past 72 hours.This study is best described as a(n) _________________ study.

In many real-world settings, it is not possible or feasible to know the characteristics of the population.Because we cannot safely assume these characteristics, we must use the information from a sample to answer questions concerning the population.In such cases, we are dealing with a(n) ______________ problem.

A volleyball coach records information about each serve in one game to determine if use of a jump serve rather than a standard overhand serve is more likely to lead to winning a point.This is an example of using: