Real-life Examples of Mean, Median, and Mode in Psychological Research

📚 Quick Study Guide

• 🔢 Mean: The average of a dataset. Calculated by summing all values and dividing by the number of values. Formula: $\text{Mean} = \frac{\sum x_i}{n}$, where $x_i$ represents each value and $n$ is the number of values.
• 📊 Median: The middle value in a dataset when the values are arranged in ascending order. If there's an even number of values, the median is the average of the two middle values.
• 📈 Mode: The value that appears most frequently in a dataset. A dataset can have one mode (unimodal), multiple modes (multimodal), or no mode.

Practice Quiz

1. Question 1: A researcher is studying the effects of sleep deprivation on cognitive performance. They collect data on the number of errors participants make on a task after 24 hours of sleep deprivation. The data set is: 5, 7, 7, 9, 10, 12, 15. What is the mode of this data set?
   1. 5
   2. 9
   3. 7
   4. 15
2. Question 2: In a study examining the effectiveness of a new therapy for anxiety, a psychologist measures participants' anxiety levels before and after treatment. The 'after' scores are: 3, 4, 4, 5, 6, 6, 6, 7. What is the median anxiety level after treatment?
   1. 4
   2. 5
   3. 5.5
   4. 6
3. Question 3: A school psychologist wants to determine the typical number of books read by students in a class during the summer. The number of books read by each student is: 2, 2, 3, 4, 5, 5, 5, 6, 7, 8. What is the mean number of books read?
   1. 4.5
   2. 4.7
   3. 5
   4. 5.2
4. Question 4: Researchers are investigating the reaction times of participants to a visual stimulus. The reaction times (in milliseconds) are: 200, 220, 220, 230, 240, 250. What is the mode of the reaction times?
   1. 200
   2. 220
   3. 230
   4. 250
5. Question 5: A clinical psychologist is tracking the number of therapy sessions attended by patients. The data is: 5, 8, 8, 10, 12, 12, 12, 15. What is the median number of sessions attended?
   1. 8
   2. 10
   3. 11
   4. 12
6. Question 6: A developmental psychologist studies the age at which children start walking. The ages (in months) are: 10, 11, 12, 12, 13, 14, 15. What is the mean age at which children start walking in this sample?
   1. 12
   2. 12.43
   3. 12.5
   4. 13
7. Question 7: In a study on stress levels, participants rated their stress on a scale of 1 to 10. The ratings are: 4, 5, 5, 6, 7, 7, 7, 8. What is the mode of the stress ratings?
   1. 5
   2. 6
   3. 7
   4. 8