PSYC FPX 4700 Assessment 2 Central Tendency and Probability

PSYC FPX 4700 Assessment 2 Central Tendency and Probability

Student Name

Capella University

PSYC FPX 4700 Statistics for the Behavioral Sciences

Prof. Name:

Date

Central Tendency and Probability

Problem Set 2.1: Characteristics of the Mean

To investigate perception, a researcher selects a sample of participants (n = 12) and asks them to hold pairs of objects that differ in weight but not in size, one in each hand. The researcher requests that participants report when they first notice a difference in the weight of the two objects. Below is a list of the differences in weight (in pounds) when participants first detected a difference. Answer the following questions based on the data provided in the table.

Difference in Weight

4
8
9
5
12
7
6
15
10
4
8
8

State the following values for this dataset:

Mean ___

Median ___

Mode(s) ___

What is the shape of this distribution? Hint: Use the values of the mean, median, and mode to infer the shape of this distribution. ___

Problem Set 2.2.a: Interpret Means in a Chart

General life satisfaction across cultures. Gilman and colleagues (2008) measured general life satisfaction in 1,338 adolescents from two individualistic nations (Ireland, United States) and two collectivist nations (China, South Korea) using the Multidimensional Students’ Life Satisfaction Scale (MSLSS). The mean participant scores on the MSLSS are presented in the following table.

PSYC FPX 4700 Assessment 2 Central Tendency and Probability

Among which group was general life satisfaction lowest on average? __

Among which group was general life satisfaction highest on average? __

Problem Set 2.2.b: Understanding Standard Deviations in a Chart

Acceptable height preferences. Salska and colleagues (2008) examined height preferences among dating partners. In their first study, they analyzed Yahoo! Personals for heterosexual individuals living within 250 miles of Los Angeles, California, and recorded the acceptable range of heights for their dating partners. The following table summarizes some of the results.

Overall, did men or women exhibit greater variability in their responses? Explain.

Problem Set 2.3: Range, Variance, and Standard Deviation in Excel

A sample of likes per post on Facebook: 45, 789, 16, 5, 486, 1, 87, 18, 48, 1

Problem Set 2.4: Range, Variance, and Standard Deviation in JASP

Use the dataset likes.jasp. This dataset contains a sample of likes per post on Facebook.

Answer: Does your mean equal the mean calculated in Problem Set 2.3? __

Problem Set 2.5: Probability and Conditional Probability

Researchers often seek to understand the likelihood of sampling outcomes. They may inquire about the probability that a person with a specific 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 new and returning students living on or off campus. The population is summarized in the following table.

Problem Set 2.6: Determining Probability

Probability of first marriage among women. A report from the National Center for Health Statistics (NCHS) by the Centers for Disease Control and Prevention (CDC) in 2009 indicated that approximately 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 this 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?

18 years of age: ___

25 years of age: ___

30 years of age: ___

Problem Set 2.7: Understanding Normal Distribution

Judging the humor of “lawyer” jokes. Stillman et al. (2007) conducted a study where participants listened to various jokes. To assess the funniness of the jokes, 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, with a rating of 14.48 ± 4.38 (M ± SD).

Assuming that these data are normally distributed,

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

How many of the 86 undergraduates rated the joke at least a 10? ___

Problem Set 2.8: Calculating z Scores in JASP

Use the dataset ratings.jasp. This dataset records how a sample of senior citizens rated the Internet on a 1–10 scale, with 1 being “really distrust it” and 10 being “completely trust it”:

PSYC FPX 4700 Assessment 2 Central Tendency and Probability

Answer: Which number of ratings is closest to the z score of 0?