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

ASSIGNMENT 4 WORKSHEET
There are four (4) parts to this assignment. Be sure to complete each section according to the instructions listed below. Complete all sections in a single MS Word document and upload it to the assignment page. Label each section as shown below. Ensure you follow the guidelines listed below when completing this assignment.  GUIDELINES

Use proper APA formatting.
Provide in-text citations for each part as appropriate.
Be sure you proofread before submitting. Your assignment must be free of spelling and grammatical errors.
Include a reference list.
Include a Turnitin plagiarism report.
Each part of the assignment (i.e., A, B, C, D) should be at least one half of a page in length.
For Parts A & D, show your work (e.g., show each step of calculating missing numbers in the dataset and show how to calculate the confidence interval).

ASSIGNMENT COMPONENTS
Part A
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
Compare and contrast directional and non directional hypotheses. Provide an example of a directional and of a non directional hypothesis.

Part C
What is the difference between probability and non probability sampling?

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

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

Part D
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)?

In order for this result to be generalizable from the sample of 3,000 to the population of interest, what type of sampling technique should be used? Why?