Ap stats chapter 11-13 test

A computer network manager wants to test the reliability of some new and very expensice fiber-optic Ethernet cables that the computer department just received. The computer department received 8 boxes containing 40 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?

320 cables

We wish to compare the average ages of the math and science teachers at your high school. Which is the best way to collect the data?

Census

The human resources department of a large, well-known telecommunications firm is behind schedule is sampling the job satisfaction of the company's employees. In an effort to catch-up, the HR manager quickly goes down a list of employees and e-mails surveys to only one section of the company. As neutral third party collects all surveys and ensures all of the selected employees respond to the survey. What sampling method describes what the HR manager is doing?

Cluster Sampling

A high school was doing a survey about the pandemic. The administration had to decide whether to go all online classes or let the students return to their classrooms. The administration surveyed their friends' kids and their teachers kids that were in the high school. Identify the type of sampling used in this example.

Convenience Sampling

Which is true about sampling? I. Sampling error is usually reduced when the sample size is larger II. Sampling error is the result of random variations and is always present III. An attempt to take a census will always result in less bias than sampling

I and II only

Hoping to get information that would allow them to negotiate new rates with their advertisers, Natural Health magazine phoned a random sample of 600 subscribers. 64% of those polled said they use nutritional supplements. Which is true? I. The population of interest is the people who read this magazine II. "64%" is not a statistic; it's the parameter of interest III. This sampling design should provide the company with a reasonably accurate estimate of the percentage of all subscribers who use supplements

I and III only

Among a dozen eggs, three are rotten. A cookie recipe calls for two eggs; they'll be selected randomly from that dozen. Which plan could be used to simulate the number of rotten eggs that might be chosen? I. Let 0, 1, and 2 represent the rotten eggs, and 3, 4,..., 11 the good eggs. Generate two random numbers 0-11 ignoring repeats II. Randomly generate a 0, 1, and 2 to represent the number of rotten eggs you get III. Since 25% of the eggs are rotten, let 0 = rotten and 1, 2, 3 = good. Generate two random numbers 0-3 and see how many 0's you get

I only

Which is important in designing a good experiment I. randomization in assigning subjects to treatments II. control of potentially confounding variables III. replication of the experiment on a sufficient number of subjects

I, II, and III

The January 2005 Gallup Youth Survey successfully surveyed a random sample of 7,028 U.S. teens aged 13-17 and asked these teens to name their favorite movie from 2004. Napoleon Dynamite had the highest percentage with 8% of teens ranking it as their favorite movie. Which is true? I. The population is the movies from 2004 II. 8% is a statistic and not the actual percentage of all U.S. teens who would rank this movie as their favorite III. This sampling design should provide a reasonably accurate estimate of the actual percentage of all U.S. teens who would rank this movie as their favorite.

II and III

Hoping to get information that would allow them to negotiate new rates with their advertisers, Natural Health magazine successfully surveyed a random sample of 2600 subscribers. 64% of those polled said they used nutritional supplements. Which is true? I. The population is 64% of those polled that said they use nutritional supplements II. "64%" is a statistic; it is not the parameter of interest III. If the sample is biased, this sampling design should provide the company with a reasonably accurate estimate of the percentage of all subscribers who use supplements.

II only

Which statement about bias is true? I. Bias results from random variation and will always be present II. Bias is usually reduced when a good sample size gets even larger III. Bias results from a sampling method likely to produce samples that do not represent the population.

III only

A basketball player has a 70% free throw percentage. Which plan could be used to simulate the number of free throws she will make in her next five free throw attempts?

Let 0, 1, 2 represent missing a shot and 2, 4,..., 9 represent making a shot. Generate five random numbers from 0-9 and count how many numbers are in 3-9.

Before premiering a blockbuster movie at a theatre, 50 test screenings (at theaters) are done beforehand. Five theaters are chosen at random and then theater management interviewed every 25th theatergoer during a random weekend. Identify the type of sampling used in this example.

Multistage Sampling

Suppose the state decides to randomly test high school wrestlers for steroid use. There are 16 teams in the league, and each team has 20 wrestlers. State investigators plan to test 32 of these athletes by randomly choosing two wrestlers from each team. Is this a simple random sample?

No. because not all possible groups of 32 wrestlers could have been the sample

Of A-D, which is not a critical part of designing a good experiment?

Random selection of subjects

A computer network manager wants to test the reliability of some new and expensive fiber-optic Ethernet cables that the computer department just received. The computer department received 9 boxes containing 40 cables each. The manager does not have the time to test every cable in each box. The manager will randomly choose 3 cables from each box. What type of sampling is done here?

Stratified

The human resources department of a large, well-known telecommunications firm is behind schedule in sampling the job satisfaction of the company's employees. In an effort to catch up, the HR manager quickly goes down an alphabetical list of employees and e-mails a survey to every 10th employee. An neutral third party collects all surveys and ensures all of the selected employees respond to the survey. What sampling method best describes what the HR manager is doing?

Systematic Sampling

TIME magazine mails a survey to every subscriber asking about the quality of its subscription service. The quality of its subscription service represents what?

The parameter of interest

TIME magazine mails a survey to every subscriber asking about the quality of its subscription service. The magazine finds that only 20% of subscribers that answered the survey represents what?

The sample

Computers generate pseudorandom numbers. Can these numbers be used as random numbers? Why of why not?

Yes. They are virtually indistinguishable from truly random numbers.

In an experiment the primary purpose of blinding is to reduce

bias

In an experiment the primary purpose of blinding is to reduce...

bias

Placebos are a tool for

blinding

A researcher wants to compare the effect of a new type of shampoo on hair condition. The researcher believes that men and women may react to the shampoo differently. Additionally, the researcher believes that the shampoo will react differently on hair that is dyed. The subjects are split into four groups: men who dye their hair, men who do not die their hair; women who dye their hair, and women who don't dye their hair. Subjects in each group are randomly assigned to the new shampoo and the old shampoo. This experiment...

has one factor (shampoo type), blocked by gender and whether hair is dyed

A researcher identified 100 men over forty who were not exercising and another 100 men over forty with similar medical histories who were exercising regularly. She followed all the men for several years to see if there was any difference between the two groups in the rate of heart attacks. This is a(n)

prospective study

In an experiment the primary use of blocking is to reduce

variation

The human resources department of a large, well-known telecommunications firm is behind schedule in sampling the job satidfaction of the company's employees. In an effort to catch-up, the HR manager quickly sends out a survey by email to all of it's employees. 78% of the employees respond to the survey. What sampling method best describes what the HR manager is doing?

volunteer sampling