Exam 10: Determining the Size of a Sample

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.

Which of the following is true with regard to variability?

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.

95 percent of the observations under the normal curve fall within ________ times the sample error.

Which of the following is true regarding a probability sample?

Sample accuracy refers to:

The size of a probability sample depends on the client's desired accuracy (acceptable sample error)balanced against the cost of data collection for that sample size.

The sample size determines:

If we were to graph the relationship of sample size (x axis)to sample accuracy (y axis),we would notice that:

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

The basic difference between an arbitrary and a conventional sample size determination is that:

The sample size is always related to how representative the sample is of the population.

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

Which of the following is the theory that allows us to say that if we conducted a survey 1,000 times,and we were to plot the answers to our survey,the plot would appear as a normal curve?

Sample error may only be determined after data have been collected.Even if we know the level of confidence,an estimate of variability (p∗q)and the sample size,n,we cannot compute the amount of sample error we can expect to experience.

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

What three factors are needed to calculate sample size?

Dot Miller owns a small chain of dive shops.She is interested in knowing how many potential customers she will need to sample in several large cities within a three- to four-hour drive of her shops located on the California coast.She wants to estimate the mean response to a 10-point scale measuring the likelihood that they will subscribe to a dive package which,if they take advantage of all the dives,represents a savings of 50 percent over taking the dives individually.In estimating the standard deviation in the population for the formula for calculating the sample size for estimating a mean,Dot can:

If we know the level of confidence (1.96 for 95 percent),variability estimates,and the size of a sample,there is a formula that allows us to determine:

If we are using the sample size formula to be used when estimating a mean and we are trying to determine s,we are trying to indicate: