8. Sampling and Statistical Quality Control Flashcards
Define standard deviation.
Standard deviation is a measure of the dispersion of a set of data from its mean.
__________ is the percentage of times that a sample is expected to be representative of the population.
Confidence level.
__________ is the range around a sample value that is expected to contain the true population value.
Confidence interval.
List the measures of central tendency.
*Mean
*Median
*Mode
Why is the median the best estimate of central tendency for many asymmetrical distributions?
The median is not biased by extremes.
The subjective determination of sample size and selection is
Judgmental sampling.
The quantitative determination of sample size and selection is
Statistical sampling.
Define sampling risk.
The risk that a sample is not representative of the population.
Which sampling approach gives all items in the population an equal chance of being selected?
Random sample.
Name the two approaches to sampling.
*Nonstatistical
*Statistical
What are the disadvantages of judgmental sampling?
*It does not provide a quantitative measure of sampling risk.
*It does not provide a quantitative expression of sample results.
*If the auditor is not proficient, the sample may not be effective.
If deviations exist in the population, which attribute sampling method ensures the sample includes at least one deviation?
Discovery sampling.
Reducing or enlarging the sample size based on the deviation rate in the population is
Stop-or-go (sequential) sampling.
List the factors that sample size for an attribute test depends on.
*Confidence level
*Population size
*Expected deviation rate (expected rate of occurrence)
*Tolerable deviation rate (desired precision)
Define the sample deviation rate.
The sample deviation rate is the number of deviations observed in a sample divided by the sample size. This rate is the best estimate of the population deviation rate.
What are the five variables sampling techniques?
1.Unstratified mean-per-unit
2.Stratified mean-per-unit
3.Difference estimation
4.Ratio estimation
5.Monetary unit sampling
What information is provided by variables sampling?
Variables sampling provides information about whether a stated amount (e.g., the balance of accounts receivable) is materially misstated.
__________ are graphic aids for monitoring the status of any process subject to acceptable or unacceptable variations during repeated operations.
Statistical control charts.
The limits of controls should be set so that the cost of an investigation is
Less than or equal to the benefits derived.
What does acceptance sampling determine?
Acceptance sampling determines the probability that the rate of defective items in a batch is less than a specified level.
What is a Pareto diagram?
A Pareto diagram is a bar chart that assists managers in what is commonly called 80:20 analysis, which states that 80% of all effects are the result of only 20% of all causes.
__________ is the separation of a population into logical groups (subpopulations).
Stratification.
