Question 1

There is a separate sample size formula for estimating a percentage of the population than for estimating a mean of the population.

Accepted Answer

The sample size formula for estimating a percentage involves the use of the proportion (p) and the margin of error (E), while the sample size formula for estimating a mean involves using the standard deviation (σ), the margin of error (E), and the population size (N). Therefore, the formulas are different for these two types of estimates.

Question 2

The desired accuracy should NOT be considered in order to calculate the proper sample size. This is because accuracy cannot be determined until the data are collected and analyzed.

Accepted Answer

The answer of The desired accuracy should NOT be considered...

Question 3

Using the confidence interval formula for calculating sample size, the amount of variability believed to be in the population must be estimated.

Accepted Answer

Estimating the population variability, known as the standard deviation, is crucial for calculating sample size using the confidence interval formula. This estimate helps in determining how much sample size is required to ensure the confidence level and margin of error are met.

Question 4

It is "true" to say that, in practice, you can estimate variability in the population by using one of three methods: (a)set pq to the most conservative amounts of 50 percent/50 percent, (b)estimate pq based upon prior research studies, or (c)conduct a pilot study.

Accepted Answer

This statement is true. These are some common methods to estimate the variability in the population. However, it is important to note that the reliability and accuracy of these estimates may vary depending on the specific research context.

Question 5

Variability (standard deviation)of a population where a mean is being estimated may be estimated by dividing the range by 6.

Accepted Answer

The answer of Variability (standard deviation)of a population where a...

Question 6

It is almost always up to the researcher to educate the manager on what might be acceptable or "standard" sample error.

Accepted Answer

The researcher is the expert in sampling techniques and statistical analysis, and thus it is their responsibility to inform the manager on what sample error is acceptable or typical in the industry.

Question 7

The most significant factor in calculating sample size (n)is the size of the population (N). For example, if you calculated that you needed a sample size of 300 in order to have an accurate sample for your hometown, it would take at least 10 times this amount, or about 3,000, in order to have an accurate sample representing the entire United States.

Accepted Answer

The answer of The most significant factor in calculating sample...

Question 8

The arbitrary approach to sample size determination takes the desired level of accuracy into account.

Accepted Answer

The arbitrary approach to sample size determination does not consider the desired level of accuracy, but rather relies on a predetermined or convenient sample size.

Question 9

The only time that the population size is a consideration in sample size determination is in the case of a "small population."

Accepted Answer

For small populations, sample size determination takes into account the population size as it can affect the representativeness of the sample. For larger populations, the sample size is determined based on the level of precision desired and the variability of the population, without taking population size into consideration.

Question 10

In a "Yes/No" question, 50 percent "Yes" and 50 percent "No" shows less variability than does 90 percent "Yes" and 10 percent "No."

Accepted Answer

90 percent "Yes" and 10 percent "No" shows greater variability because there is a larger range of responses.

Question 11

Using the confidence interval formula for calculating sample size, the level of confidence desired to the estimate of the population values must be determined and is represented in the formula by the z value.

Accepted Answer

The statement is true. The level of confidence desired is represented by the z value in the formula for calculating sample size using the confidence interval.

Question 12

In sample size formulae, acceptable sample error is noted by "e."

Accepted Answer

The acceptable sample error is commonly denoted by the letter "e" in sample size formulae.

Question 13

If you calculate sample size with an e of 3 percent, and then you decide to change e to 5 percent, the required sample size will go up.

Accepted Answer

The answer of If you calculate sample size with an...

Question 14

In determining the level of confidence, any level of confidence is possible, but marketing researchers typically use between 60 percent and 100 percent , depending on the importance of the issue and how much the client has to spend on the research.

Accepted Answer

The answer of In determining the level of confidence, any...

Question 15

Researchers should follow to the sample size formula closely when calculating sample size. No other consideration, such as the cost to the client, should be considered, as it will surely lower the accuracy of the study.

Accepted Answer

While researchers should strive to follow the sample size formula as closely as possible, it is important to consider other factors such as cost, feasibility, and practicality. Making adjustments to the sample size based on these factors can still result in a valid and reliable study, as long as the adjustments are carefully considered and justified.

Question 16

With the 99% level of confidence, the corresponding z value is 2.58.

Accepted Answer

This is true as the z-value associated with a 99% confidence level is indeed 2.58.

Question 17

The conventional approach to sample size determination follows some convention or number believed somehow to be the "correct" sample size.

Accepted Answer

Conventional approach to sample size determination involves using a formula or a convention to arrive at a sample size that is believed to be sufficient for the study. However, there is no universally accepted "correct" sample size, as it depends on various factors such as the research question, study design, statistical power, effect size, and variability in the data.

Question 18

A probability sample size can be a very tiny percent of the population size and still be very accurate (have little sample error).

Accepted Answer

This is true because the accuracy of a probability sample size depends on several factors such as the variability of the population, the desired level of precision, and the sample design. A small probability sample size can be accurate if it is well-designed and representative of the population. However, in general, larger sample sizes tend to have less sample error and provide more accurate estimates.

Question 19

The axiom: "You can take any finding in the survey, replicate the survey with the same probability sample size, and you will be very likely to find the same finding within the +/- percent range of the original finding" is based on the idea of the confidence interval.

Accepted Answer

The idea of the confidence interval is to provide a range of values within which a population parameter is likely to fall based on a sample. The larger the sample size, the smaller the margin of error or the range of values of the confidence interval. Therefore, if a survey finding is replicated with the same probability sample size, it is likely to produce similar results within the same margin of error, which is expressed as a percentage.

Question 20

The basic concept of the central limit theorem is that all research findings are limited in their application simply because they are based upon a sample and not a census.

Accepted Answer

The basic concept of the central limit theorem is that for large sample sizes, the sample mean will follow a normal distribution regardless of the population distribution. This theorem allows us to make inferences about the population based on the characteristics of the sample. It does not suggest that research findings are limited in their application simply because they are based on a sample.

Quiz 13: Determining the Size of a Sample