Test Questions & Answers Chapter 11 Inferential Statistics

Chapter 11 Inferential Statistics

True False

T/F. Unlike descriptive statistics, inferential statistics use mathematical equations to generate probabilities, draw associations, and make predictions about a population. (pg. 167)

T/F. Paired samples t-tests look at one group of individuals tested twice, such as with a pretest and post-test. (pg 183)

T/F. Correlations depict two concepts: direction and strength. Direction is the concept that determines whether the relationship is strong or weak. (pg 187)

T/F. Confidence intervals provide a range with a lower and upper limit, of where the mean score of the population is likely to be contained. Since researchers only have data from the sample, they estimate this range from the data collected from the sample representing the population.(pg 190)

T/F. In confidence intervals, if the lower and upper values include 0, the researchers reject the hypothesis. (pg 193)

T/F. Researchers make a Type II error when they fail to reject the null hypothesis when looking at differences between the intervention group and the study group of a study, when in fact there truly is a difference. (pg 194)

Multiple Choice:

A scientific hypothesis is a (pg. 169):

1. A question about the population that if contradictory to the null hypothesis allows researchers to reject the null hypothesis.
2. A question of interest in the evaluation project or research study. It provides a clear and concise roadmap in which to focus the study.
3. Is an “educated guess” based on prior observation, knowledge or experience that can be supported or refuted through observations or experiment.
4. None of the above.

Independent t-tests determine are used to determine if (pg 176):

1. There is a statistical difference in groups that are not normally distributed.
2. There is a statistical difference in two groups measured at one point in time.
3. There is a statistical difference in one group measured at different points in time.
4. There is a statistical difference in two groups measured at different points in time.

For negative correlations, as the scatter plot dots become more widely dispersed (pg. 188):

• 1. The strength weakens to close to 0.
  2. The strength increases to close to 0.
  3. The strength weakens to close to -1.
  4. The strength increases to close to -1.

Chose the most accurate statement regarding confidence intervals (pg 190):

• 1. In most cases, researchers set the level of confidence at 95%, so they can state that they are 5% certain that the lower and upper range of the calculated confidence interval captures the mean score of the population.
  2. In most cases, researchers set the level of confidence at 5%, so they can state that they are 95% certain that the lower and upper range of the calculated confidence interval captures the mean score of the population.
  3. In most cases, researchers set the level of confidence at .5%, so they can state that they are 95% certain that the lower and upper range of the calculated confidence interval captures the mean score of the population.
  4. In most cases, researchers set the level of confidence at 95%, so they can state that they are 95% certain that the lower and upper range of the calculated confidence interval captures the mean score of the population.

If a research null hypothesis is correct and researchers reject it, what has happened (pg 194)?

• 1. Researchers have made a Type I error
  2. Researchers have made the correct decision
  3. Researchers have made a Type II error
  4. Researchers have made a measurement error

Fill In the Blank

T-tests are used to determine if the ______________________ between two groups are statistically different. (pg 174)

Correlation coefficients define a ____________________ between two continuous variables. (pg 186)

It is essential to remember that with correlations, one variable does not mean that it ____________ another variable to change, it simply means that two things are ____________________________________________. (pg 186)