Statistics homework help. Week 4: Probability

Complete the following problems within this Word document. (Do not submit other files.) Show your work for problem sets that require calculations. Ensure your answer to each problem is clearly visible. (You may want to highlight your answer or use a different font color to set it apart.)

Submit the document to your instructor by Sunday, 11:59 p.m. central time.

Problem Set 4.1: Probability and Conditional Probability

Criterion: Compute the probability.

Instructions: Read the following and answer the questions.

Researchers are often interested in the likelihood of sampling outcomes. They may ask questions about the likelihood that a person with a particular characteristic will be selected to participate in a study. In this exercise, we will select a sample of one participant from the following hypothetical student population of men and women living on or off campus. The population is summarized in the following table.

Male Female Row Totals

On campus 30 25 55

Off campus 20 25 45

Column Totals 50 50 100

1. What is the probability of selecting a male participant? _______________________

2. What is the probability of selecting a female participant? ______________________

3. What is the probability of selecting a student who lives on campus? _____________

4. What is the probability of selecting a student who lives off campus? _____________

5. What is the probability of selecting a male student, given that he lives off campus? _______________________

6. What is the probability of selecting a female student, given that she lives on campus? _______________________

7. What is the probability of selecting a male student, given that he lives on campus? _______________________

8. What is the probability of selecting a female student, given that she lives off campus? _______________________

9. What is the probability of selecting a student who lives on campus, given that he is a male? _______________________

10. What is the probability of selecting a student who lives off campus, given that he is a male? _______________________

11. What is the probability of selecting a student who lives on campus, given that she is a female? _______________________

12. What is the probability of selecting a student who lives off campus, given that she is a female? _______________________

Problem Set 4.2: Determining Probability

Criterion: Determine the probability.

Instructions: Read the following and answer the question below.

Probability of first marriage among women. A National Center for Health Statistics (NCHS) brief report by the Centers for Disease Control and Prevention (CDC) in 2009 identified that about 6% of women in the United States married for the first time by their 18th birthday, 50% married by their 25th birthday, and 74% married by their 30th birthday.

Based on these data, what is the probability that in a family with two daughters, the first and second daughter will be married by each of the following ages?

1. 18 years of age:___________________________

2. 25 years of age:___________________________

3. 30 years of age:___________________________

Problem Set 4.3: Understanding Normal Distribution

Criterion: Solve problems with information about normal distributions and probabilities.

Instructions: Read the following and answer the questions.

Judging the humorousness of “lawyer” jokes. Stillman, Baumeister, and DeWall (2007) conducted a study where participants listened to a variety of jokes. To determine how funny the jokes were, the researchers asked a group of 86 undergraduates to rate the jokes on a scale from 1 (very unfunny) to 21 (very funny). Participants rated a “lawyer joke” as one of the funniest jokes, with a rating of 14.48 ± 4.38 (M ± SD).

Assuming that these data are normally distributed:

1. What was the rating that marks the cutoff for the top 10% of participant ratings for this joke? ___________________________

2. How many of the 86 undergraduates gave the joke a rating of at least 10? ___________________________

Problem Set 4.4: Calculating z Scores in SPSS

Criterion: Calculate z scores using SPSS.

Data: The following is a list of how senior citizens rated the Internet on a 1–10 scale, with 1 being “really distrust it” and 10 being “completely trust it”: 8, 9, 4, 6, 8, 5, 1, 9, 7, 6

Instructions: Complete the following steps:

a. Enter the data into SPSS using the variable name Rating.

b. In the Toolbar, click Analyze, select Descriptive Statistics, and then select Descriptives.

c. Select Goals and then click Arrow to send data over to the right side of the table. Check the box Save Standardized Values as Variables.

d. Select Options, check the boxes Mean and Standard Deviation, and then deselect all other boxes. Click Continue.

e. Click OK and then copy and paste the descriptive statistics table below.

f. Go to the Data View in SPSS. You will see that the z scores have been added to the file. Paste a screenshot of the Data View, showing the z scores, into the Word document.

g. Answer: Which number of goals is closest to the z score of 0?

Problem Set 4.5: Define Problem for Final Paper

Criterion: Define a problem in the social sciences.

Instructions: Write a well-written paragraph that includes the following:

a. Topic sentence establishing the topic and variables.

b. Evidence of what the problem is.

c. Evidence of how many people have the problem.

Problem Set 4.6: Literature Review, Part 1

Criterion: Synthesize sources.

Instructions: Write two well-written paragraphs that include the following:

a. Topic sentence with main idea.

b. Evidence from at least two different sources that support the main idea.

c. An analysis explaining how the evidence relates to the topic sentence or how the main idea relates to the problem (established in Problem Set 4.5).