Exam 2: An Introduction to Statistics

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:

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

In a statistical inference procedure,the claim is BEST described as a statement:

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:

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 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:

An office manager wishes to survey 5 of her 20 employees for whom she is responsible.She assigns each of the 20 employees a number and writes the number on 20 identical but separate pieces of paper.She places the 20 paper pieces in a hat,mixes them up,and then blindly draws five numbers to determine which five employees are included in the sample.If the slips of paper are identical and the selection of each is blind,is this a simple random sample of size 5?

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:

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

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

Lenders base the eligibility of home loans on a perspective borrower's credit score.Recent failures of lending corporations have prompted study into the adherence of lenders in general to these lending guidelines.Two thousand home loans extended between the years 1995 and 2005 were randomly selected for audit.The borrower's credit score was recorded and compared with the normal benchmark for the loan offered.The population in this study is:

Which of the following is a good estimate of the probability of lung cancer for a typical American adult?

A quality control engineer oversees the production of rubber seals for aircraft manufacturing.In a standard production run,25 seals are randomly selected for destructive testing.The seals are physically stressed to their common design limit while exposed to increasing temperature.Of interest is the temperature at which the seal fails.The variable in this experiment is:

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

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 major pharmaceutical company is conducting clinical trials on a new drug they want to bring to market.They survey 2000 people who have a 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:

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 sample in this study is:

The registrar at a small liberal arts college computes description summaries for all members of the entering class on a regular basis.For example,the average high school GPA for the entering students in the most recent year was 3.16.The Chemistry department is interested in helping all students who wish to take a chemistry class identify the appropriate course,so they offer a placement exam.They randomly select a subset of 175 students who took this exam during the past decade,and found they had an average score on the exam of 71.05.The population of interest to the Chemistry department in this study is:

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