
which are true?
I. categorical variables are the same as qualitative variables
II. Categorical variables are the same as quantitative variables
III. Quantitative variables can be continuous variables
I and III

which is true?
I. When the margin of error is small, the confidence level is high.
II. when the margin of error is small, the confidence level is low.
III. A confidence interval is a type of point estimate
IV. a population mean is an example of a point estimate
II and III

which are true?
I. the standard error is computed solely from sample attributes
II. The standard deviation is computed solely from sample attributes
III. The standard error is a measure of central tendency.
I only

which of the following is a discrete variable?
I. The average height of a randomly selected group of boys.
II. The annual number of sweepstakes winners from New York City.
III. The number of presidential elections in the 20th century.
II only

Which of the following statements are true? (Check one)
I. A sample survey is an example of an experimental study.
II. An observational study requires fewer resources than an experiment.
III. The best method for investigating causal relationships is an observational study.
II only

Which of the following statements are true?I. Random sampling is a good way to reduce response bias.
II. To guard against bias from undercoverage, use a convenience sample. III. Increasing the sample size tends to reduce survey bias.
IV. To guard against nonresponse bias, use a mailin survey.
None of the above

Suppose a researcher conducts an experiment to test a hypothesis. If she doubles her sample size, which of the following will increase?
I. The power of the hypothesis test.
II. The effect size of the hypothesis test. III. The probability of making a Type II error.
I only

With respect to experimental design, which of the following statements are true?
I. Blinding controls for the effects of confounding.
II. Randomization controls for effects of lurking variables.
III. Each experimental factor has one treatment level.
II only

In hypothesis testing, which of the following statements is always true?
I. The Pvalue is greater than the significance level.
II. The Pvalue is computed from the significance level.
III. The Pvalue is the parameter in the null hypothesis.
IV. The Pvalue is a test statistic.
V. The Pvalue is a probability.
V only

In the context of regression analysis, which of the following statements are true?
I. When the sum of the residuals is greater than zero, the model is nonlinear.
II. A random pattern in the residual plot indicates that linear regression is appropriate.
III. Influential points always reduce the correlation coefficient.
II only

Which of the following statements are true?
I. A completely randomized design offers no control for lurking variables.
II. A randomized block design controls for the placebo effect.
III. In a matched pairs design, subjects within each pair receive the same treatment.
None of the above

In the context of regression analysis, which of the following statements are true?
I. A linear transformation increases the linear relationship between variables.
II. A logarithmic model is the most effective transformation method.
III. A residual plot reveals departures from linearity.
III only

Which of the following would be a reason to use a onesample ttest instead of a onesample ztest?
I. The standard deviation of the population is unknown.
II. The null hypothesis involves a continuous variable.
III. The sample size is large (greater than 40).
I only

A study of voting chose 663 registered voters at random shortly after an election. Of these, 72% said they had voted in the election. Election records show that only 56% of registered voters voted in the election. Which one is statistic and which is parameter?
 72% is statistic
 56% is parameter

