Chapter 8

Question 1

A sample selected so that each item or person in the population has the same probability or chance of being included

Answer 1

Simple Random Sampling

Question 2

A random starting point is selected, and then every kth member of the population is selected. Used when it’s difficult to assign random numbers.

Answer 2

Systematic random sampling

Question 3

When should random sampling not be used

Answer 3

When physical order of the population is related to the population characteristics

Question 4

A sample where the population is divided into subgroups called strata, and a sample is randomly selected from each stratum

Answer 4

Stratified random sampling

Question 5

When a population is divided into cluster using naturally occurring geographic or other boundaries. Then, clusters are randomly selected and sample is collected by randomly selecting from each cluster.

Answer 5

Cluster sampling

Question 6

List four reasons we use sampling

Answer 6

1. To time consuming to do population
2. Cost would be prohibitive to do population
3. The physical impossibility of checking all items in the population
4. The destructive nature of some tests

Question 7

The probability distribution of all possible sample means of a given sample size

Answer 7

Sampling distribution of the sample mean

Question 8

How are sample means distributed? What does this tell us

Answer 8

Normal distribution. That they follow the empirical rule

Question 9

What are 3 important relationships between the populations distribution and the sampling distribution

Answer 9

1. The mean of the sample means is equal to the populations mean
2. The dispersion of the sampling distribution is narrower than the population distribtution
3. The sampling distribution of the sample mean tends to be bell shaped and approximate the normal probability distribution

Question 10

Theorem that states all samples of a particular size are selected from any population, the sampling distribution of the sample mean is approximately a normal distribution

Answer 10

Central Limit Theorem

Question 11

Because it can be demonstrated that the mean of the sampling distribution is exactly equal to the population mean, the standard deviation of the sample mean is
standard deviation/square root of n

Answer 11

Standard error of the mean

Question 12

how do you find the z-value of a sample mean when the standard deviation is known

Answer 12

z= sample mean - population mean/standard deviation divided by square root of sample

Question 13

The fraction, ratio, or percent indicating the part of the sample or population having a particular trait of interest.

Answer 13

Proportion

Question 14

Sample portion formul

Answer 14

P=x/n where P is the proportion, x is the number of successful outcomes, and n is the sample size

Question 15

The difference between a sample statistic and its corresponding population parameter

Answer 15

Sampling error