#### Research

Part A (15 points)

Using an example (be creative) define and explain degrees of freedom.

The formula for calculating degrees of freedom for this assignment is N – 1.

If N = 10 and the mean of your sample = 77.1, solve for the score X below.

52, 5, 97, 175, 40, 104, 130, 39, 117, X

X = ? (Hint, the answer is not 9).

Part B (15 points)

Compare and contrast directional and nondirectional hypotheses. Provide an example of a directional and of a nondirectional hypothesis.

Part C (15 points)

What is the difference between probability and nonprobability sampling?

Provide an example of probability and an example of nonprobability sampling.

What is the best type of sampling procedure a researcher can use to generalize from a sample to a population? Why?

Part D (15 points)

What are confidence intervals?

What are two things that can affect the range (i.e., width) of a confidence interval. Explain your answer.

A newspaper report is concerned with whether adults think children under 10 should drink caffeine. Of the 3,000 adults who participated in this study, 73% thought that children under 10 should not drink caffeine. The report claimed that the margin of error for this result is 5%.

What is the confidence interval for this report (i.e., report the actual range of scores)?