STUDY.COM BUS 212-CHAPTER 9

What type of distribution pattern must a population have in order to use the central limit theorem?

All of these can be used

What is a sequence of equally distributed variables?

Random sample

A _____ is a part of a population used to describe the whole group.

Sample

What is a type of random sampling where the variables have an equal, and unsystematic, chance of selection?

Simple random sampling

Which of the following is TRUE, according to the central limit theorem?

The variance of the population can be approximated by the variance of the sample means divided by the sample size.

To find the interval you need, take your population divide by the _____.

sample size

What does the normal distribution look like?

A bell

When members belong to multiple groups in the population this is called _____. Cluster sampling _____ have this.

crossover; cannot

Which of the following type of error will always happen no matter how you design your study?

Random Error

Why might a researcher use a sample rather than an entire population for their study?

Using a sample is more practical than using an entire population.

_____ is a sampling method where different groups within a population are used as a sample.

Cluster sampling

Which of the following explains the difference between probability and non-probability sampling?

In a probability sample, the participants are chosen randomly, while in a non-probability sample the participants are chosen non-randomly.

What is a part of a population used to describe the whole group?

Sample

To use systematic random sampling, you must first create a list of your population, and then:

Select a beginning number

Analyze the following statements and indicate which one best describes the difference between the population and the sample.

The population is all members of a specified group while the sample is the part of a population used to describe the whole group.

Which is a sampling method that involves separating the population into clusters, and then selecting random samples from each of the clusters?

Two-way cluster sampling.

When doing systematic sampling, you must remember that all outcomes must be given _____ chance of being selected.

equal

What is the distribution pattern of data that the central limit theorem makes use of?

A normal distribution

Why is systematic random sampling unbiased?

Because the system selects the sample rather than an individual

You should use cluster sampling when the clusters are _____ in a population.

Natural

Matthew is worried that the results of his study may not be valid because the majority of his sample did not return their surveys. Which type of error is Matthew worried about?

Non-response Error

What is the name for all the members of a specified group?

Population

Based on the central limit theorem application, which of the following statistical processes would not become easier to describe or analyze?

Relative variable importance

According to the central limit theorem, if multiple independent variables have the same relative effect on an outcome, what is the result of summing those variables?

The sums will be normally distributed

A biologist has a sample of lizards from a certain area, and their weights are normally distributed. If the biologist wants to expand the sample, but maintain its integrity, what should they do? Why?

They should randomly choose lizards from the same area, because the data set only maintains its integrity if the new members of the sample come from a random sampling.

When selecting strata groups, it is recommended you have:

No more than 4 to 6 strata.

A(n) _____ is all members of a specified group.

Population

A scientist is measuring the diameters of tree trunks, measuring twenty trees per trip. If the scientist increases their sample size to thirty per trip, then what change should they expect to see in the means of the samples?

They will become more normally distributed.

Which type of random sampling divides members of a population into homogeneous subgroups?

Stratified random sampling

How do cluster sampling and stratified random sampling differ?

Stratified random sampling requires selection from each group proportional to their share of the population, but cluster sampling does not.

What is a Z-score?

The measure of distance from the mean in terms of numbers of standard deviation

What is the method that requires selecting samples based on a system of intervals in a numbered population?

Systematic random sampling

The central limit theorem looks at what specific values derived from a population?

The mean of multiple samples

Mario is worried that the results of his study may not be valid because he suspects that there is a problem with the sample that he chose. Which of the following types of error is Mario worried about?

Systematic Error

Mattie is worried that the difference between the results of her study and what is actually true for the population may be too large. Which of the following would best define what is Mattie worried about?

The error of her study.

For which type of study is it most appropriate to use a random sample?

To gather information about a large population.

Jackie is conducting a survey. Her population contains 100 people with strata divided into the following proportions: 20%, 10%, 10%, 30%, 30% If Jackie wants to select 10 people for her sample, then how many people from each stratum would she pick?

She would randomly select 2, 1, 1, 3, and 3 individual(s) from each stratum respectively.

What does the central limit theorem state?

The more you run a random experiment, the more its results will follow a normal distribution.

Marco is conducting an experiment on training certain breeds of dogs. He wants to know how long, on average, it would take to teach a Labrador to fetch an object. He gets a group of dogs to conduct his experiment. 5 of the dogs are Labradors and 3 of the dogs are Dalmatians. What is the population and sample in this experiment?

The population is all Labradors, and the sample is the 5 Labradors that Marco trained.

Sandra is selling her new line of all natural make-up products and wants to know the popularity of certain colors among teenagers. She hands out a survey to all of the students in her teenage daughter's class and asks them to identify their favorite make up colors. Which is the population and which is the sample in this scenario?

The population is all teenagers, and the sample is the teenagers in Sandra's daughter's class.

A researcher is studying a population, and decides to use simple random sampling. Why might they have made this decision?

The researcher doesn't know a lot about the population.

Which of the following statements is an implication of the central limit theorem?

The standard deviation of the population can be approximated by the standard deviation of the sample means divided by the square root of the sample size.

Assuming that the population is not normally distributed to begin with, what will happen to the sample means with a large enough sample size?

They will be normally distributed.

Which of the following is a type of random sampling?

Cluster sampling

Which of the following conditions must be met for a sample to be a stratified random sample?

It must include all members of a population.

Elizabeth is waiting for her flight at the airport. She decides to conduct an experiment. She wants to know how many people at the airport carry a laptop with them for their flight. She sees 50 people walk past her as she waits. Thirty of those people are carrying laptops. What is the population and sample in this scenario?

The population is everyone at the airport, the sample is the 50 people that walked by Elizabeth.

Stratified random sampling works best when the researcher is familiar with the demographics of the population and:

The proportion of the demographics are important to the data being collected.

Simple random sampling is usually done _____.

without replacement

Which of the following is an implication of the central limit theorem?

The mean of the population can be approximated by the mean of the sample means.

What is the name for the line that goes through the mean of a normal distribution curve?

Central line