Exam 10: Sample Surveys

A Statistics instructor wishes to know the average age (in month)of his 200 students.He decides to choose 25 students from the class and ask them for their age.All 200 names are put in a hat and 25 names are then chosen at random (without replacement).The average age of the students chosen is observed to be 231 months.In this example,"200" is known as what?

A popular soft drink company distributes written surveys with its product that a customer can fill out and mailed in or the survey can be filled out electronically on the internet.What,if any,will be the most noticeable bias?

At a small college there are 120 freshmen,90 sophomores,110 juniors,and 80 seniors.A school administrator selects a random sample of 12 of the freshmen,a random sample of 9 of the sophomores,a random sample of 11 of the juniors,and a random sample of 8 of the seniors.She then interviews all the students selected.Identify the type of sampling used in this example.

A magazine publisher mails a survey to every subscriber asking about the quality of its subscription service.Mailing a survey to every subscriber represents what?

A Statistics instructor wishes to know the average age (in month)of his 200 students.He is too lazy to sample all 200 students so he decides to choose 20 students at random from the class and ask them for their age.In the class,students are sitting in twenty rows each of size ten.He randomly selects two rows of students and samples all students in those rows.This sampling method is called a

Mr.Smith works at a computer consultant company that provides technical information to computer departments of various manufacturing companies.Mr.Smith is alarmed at the number of spyware programs on the internet.Mr.Smith successfully samples every one of his clients only to ask (yes or no)if they have had any known problems with spyware infections on their computers or network.None of Mr.Smith's clients reported any spyware infections.With regards to Mr.Smith's contacting his clients,what is the census?

A computer network manager wants to test the reliability of some new and very expensive fiber-optic Ethernet cables that the computer department just received.The computer department received 7 boxes containing 50 cables each.The manager does not have the time to test every cable in each box,so the manager assigns a subordinate to do a census.How many cables will be sampled if the subordinate does a census?

A newspaper reporter decided to sample residents of all major metropolitan areas in the entire country.This sampling asked if the residents liked living in their city,or are they considering moving,and if so,where? Unfortunately,this survey went over budget and was stopped,and only the east coast of the country was adequately interviewed.With regards to having this survey labeled as representing the entire country,what,if any,will be the most noticeable bias for this survey as it is now?

A Statistics instructor wishes to know the average age (in month)of his 200 students.He decides to choose 25 students from the class and ask them for their age.All 200 names are put in a hat and 25 names are then chosen at random (without replacement).The average age of the students chosen is observed to be 231 months.The group of 25 students is known as what?

The human resources manager of a large,well-known telecommunications firm wants to improve manager/employee relationships throughout the company.This HR manager wants to have several focus groups,each filled with randomly selected managers and employees in proportion to the company's overall manager/employee ratio.What sampling method best describes what is wanted by the HR manager?

A blockbuster movie had just premiered on exactly 1257 screens throughout the country.Within the first week,a few theatres were chosen at random,and then theater management interviewed approximately 5% of the theatregoers at those selected theatres.All these theatregoers loved the movie,therefore management decided to increase the number of showings per week.Identify the type of sampling used in this example.

A newly-premiered play just ended that evening at a local theatre.Theatre management briefly interviews every eighth person leaving the theatre to see if that person will recommend the play at that theatre to other people.Identify the type of sampling used in this example.

At the end of each semester a local university requires a professor's evaluation.An evaluation survey is given to each student to fill out.Identify the type of sampling used in this example.

At the local university a survey was being done on whether or not the students liked the cafeteria food.The survey was located in the college newspaper and was to be filled out and sent to the editing office.Identify the type of sampling used in this example.

The human resources department of a large,well-known telecommunications firm is behind schedule in writing a report about the job satisfaction of the company's employees.In an effort to quickly sample some people,the HR manager orders his subordinates to give out paper surveys "to anyone you see sitting at their desk",and the survey,completed or not,will be picked up in five minutes.Only the completed surveys will be used in the report.What sampling method best describes what this HR manager is doing?

During a provincial election,a campaign manager wishes to know how well her candidate will do in the upcoming election."Who" is likely to be identified in the sampling frame?

Management at a post office is curious about its services in one small town.Every address within that town,including business and residential,is mailed a survey inquiring about the post office's quality of service.The post office does receive a respectable 25% response rate to the survey.However,what,if any,is the most noticeable bias for this survey?

A Statistics instructor wishes to know the average age (in month)of his 200 students.He is too lazy to sample all 200 students so he decides to choose 20 students at random from the class and ask them for their age.He breaks the class up into two groups,males and females.He then selects a SRS of size 10 from each gender group.This sampling method is called a

Jennifer is a quality control inspector for a well-known computer modem manufacturer.Jennifer oversees five assembly lines; each assembly line produces the same number of modems per day.Jennifer randomly selects one assembly line each morning and performs further sampling and quality control procedures on that assembly line's modems for the rest of the day.This morning,Jennifer randomly selected the modems of assembly line #5 for quality control inspection.Futhermore,Jennifer will then perform systematic sampling on that assembly line's modems.What has been excluded from being in the sampling frame today?

A magazine publisher mails a survey to every subscriber asking about the timeliness of its subscription service.The publisher finds that only 4% of the subscribers responded.This 4% represents what?