MQM 100 chp 8 study

Suppose that a particular brand of 5 inch candles has an average life of 27 hours with a standard deviation of 6 hours. If all possible samples of 4 candles were selected and the average life of the samples was determined, what would the mean of the distribution of sample means be?

27

Which one of the following describes a random process that could be used to create a simple random sample

Assigning numbers to members of the population and drawing the numbers out of a hat (the list could be used in place of a random number table)

Which of the following distinguish systematic random sampling from simple random sampling?

Systematic random sampling uses only one random choice, instead of several Systematic random sampling can be more efficient in some situations

Which one of the following scenarios is NOT representative of destructive nature of testing?

Testing a student to measure his ability to recall a commercial message

Which of the following statements that correctly describe characteristics of the set of sample means?

The distribution of sample means is nearly normal if the sample size is large The dispersion of the sample means is narrower than the population dispersion The mean of the sample means equals the mean of the population

In using a random number table to select a simple random sample, where does "randomness" occur in the process?

The manner in which number are taken from the table The table itself is the one source of randomness

What characteristic of a population requires the use of stratified random sampling to avoid bias?

The population is clearly divided into groups based on some characteristic

The central limit theorem describes the sampling distribution of the sample mean. which one of these statements is correct

The sampling distribution of the sample mean is nearly normal

Which of the following statements about the sampling distribution of the sample means is not correct

The standard deviation of the sample means is the same as that of the population (The sample means have smaller variation than the population means because the sample means are found by averaging n observations from the population.)

Pick the statement that describes the formula for the standard error of the mean in ordinary language

The standard error is equal to the population standard deviation divided by the square root of the sample size

Which one of the following must be true for the sampling distribution of the sample mean to be normally distributed

There is not requirement on the sample size if the population is normally distributed

There are many reasons why it may be undesirable to sample an entire population. Which of the following is a reason that a modest size sample may be adequate

very few problems require 100% accuracy

Destructive Testing destroys a sample in the course of measuring it. Which of the following are examples of this process?

Determining a tables maximum load capacity by increasing its load until if breaks Evaluating coffee for taste and aroma

Identify the steps required in taking a systematic random sample

Divide the population size by the sample size to find k Select every kth member of the population from the starting point Select a random starting point

Which of the following are methods of obtaining a simple random sample from the population of all students at a particular college?

Drawing 100 students names from a box Using a random number table to select 100 students Using a computer software to select 100 students

Which of the following statements are true features of the central limit theorem?

For large sample size, the distribution of sample means is independent of the shape of the population It describes the sampling distribution of the sample mean The distribution shape is approximately normal

If a researcher was studying semester loads of students, which of the following might represent strata that would be appropriate for stratified random sampling?

Grouping students by marital status Grouping students as employed and unemployed

Which of the following statements which describe valid reasons to use a sample instead of evaluating a much larger population

contacting the whole population would be only marginally more accurate than a sample To contact the entire population would be time consuming

In order to apply the central limit theorem, what assumption must be made about the shape of the population distribution

no information about the populations shape is needed