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 (MSD).

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:

1. Enter the data into SPSS using the variable name Rating.
2. In the Toolbar, click Analyze, select Descriptive Statistics, and then select Descriptives.
3. Select Ratingand then click Arrow to send data over to the right side of the table. Check the box Save Standardized Values as Variables.
4. Select Options, check the boxes Mean and Standard Deviation, and then deselect all other boxes. Click Continue.
5. Click OK and then copy and paste the descriptive statistics table below.
6. 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 zscores, into the Word document.
7. Answer:Which rating is closest to the z score of 0?