Quiz Over Chapter 6 of the 6th Edition



  1. The two main types of estimation are called _______ estimation and _______ estimation.
  2. (T/F) When a researcher uses the techniques of estimation, he/she is making a guess as to unknown characteristics of the sample based upon the known characteristics of the population.

Sampling Error
  1. What is a "sampling error"?
  2. If a population is made up of 600 males and 400 females, should you expect that a simple random sample  of 100 people will end up containing 60 males and 40 females?
  3. Can researchers prevent sampling errors by extracting stratified random samples from populations?
  4. Under what 2 unrealistic conditions would a researcher be justified in anticipating no sampling error?

Sampling Distributions and Standard Errors
  1. If 100 samples are taken from a population, with each sample having n = 25, there would be __ entries in the sampling distribution of means if the sample means are plotted.
  2. Which of the following terms is closest in meaning to the term "standard error?"
    1. computational error
    2. sampling error
    3. standard score
    4. standard deviation
  3. Suppose 10,000 random samples of the same size are drawn from a population having M=50 & SD=4.  Each sample's mean is computed and then displayed in a sampling distribution.  About ___% of the sample means would lie within one standard error of 50?
    1. 1/4
    2. 1/3
    3. 1/2
    4. 2/3
    5. 3/4
  4. In the expression SEM, the E stands for "error."  What do the S and the M stand for?
  5. (T/F) Only 1 word can legitimately be put in the blank in the phrase: "standard error of the ____"
  6. In Excerpt 6.1, what abbreviation was used for the phrase, "estimated standard error of the mean"?
  7. In Excerpt 6.3, thow many standard error bars are displayed in the figure?

Confidence Intervals: What They Look Like
  1. What does the number 10 signify in this statement: "95% CI: 10, 15"?
  2. If a researcher computes a sample mean and says "95% CI = (80-90)," could the sample mean be 95?
  3. (T/F)  Confidence intervals can be built for means & correlation coefficients but not for percentages.
  4. If the CIs presented in Excerpts 6.4-6.5 are typical, what is the most popular level of confidence used?

The Construction of Confidence Intervals
  1. In building a confidence interval, what does a researcher specify first?
    1. the two numerical values that define the interval
    2. the level of confidence desired
  2. (T/F) Using the same data, a confidence interval will get wider if the confidence level is increased.
  3. A __________ relationship exists between the size of the sample & the distance between the end points  of the confidence interval.
    1. positive
    2. negative
    3. near zero
    4. absolutely zero
  4. If based on the same 25 scores, will a 95% CI for the mean turn out the same as a 95% CI for the median?

The Proper Interpretation of Confidence Intervals
  1. (T/F)  A confidence interval indicates the probability that the population parameter lies somewhere between the numerical end points of the CI.
  2. (T/F) To interpret a CI correctly, you must imagine that lots of samples are drawn from the population.

The Advantage of Confidence Intervals Over Estimate Standard Errors
  1. Confidence intervals are more easily interpreted than "standard error intervals" because CIs take into consideration __ whereas "standard error intervals" do not.
    1. sampling error
    2. N
    3. n
  2. When does the advantage of confidence intervals over "standard error intervals" become trivial?

Point Estimation
  1. When a researcher engages in point estimation, does he/she stipulate a confidence level?
  2. What statistical concept can be used to explain why point estimation is unlikely to "hit the bullseye?"
  3. Should reliability and validity coefficients be considered to be point estimates?
  4. (T/F) Point estimation should be respected because it is used twice whenever CIs are built.

Warnings Concerning Interval and Point Estimation
  1. (T/F)  If someone says "52 ± 3," the 3 might be referring to the SD or it might be referring to the SEM.
  2. (T/F) If a researcher carefully puts his/her sample data into the proper formula, he/she will still be unable to determine the precise value of the standard error of the statistic being focused on.
  3. (T/F)  If a confidence interval is built around a correlation coefficient, it may be the case that the CI's end points are not the same distance from the numerical value of r computed from the sample data.
  4. The 2nd sentence in the final paragraph of Chapter 6 says that "the entire process of estimation requires that the data used to form the inference come from _____ ."

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Schuyler W. Huck
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