Praxis Core Academic Skills for Educators: Mathematics (5733)Statistics and ProbabilityEasy
A project manager is reviewing the completion times for 5 different tasks: 12 days, 15 days, 10 days, 18 days, and 12 days. What is the mean completion time for these tasks?
- A13.4 days
- B12 days
- C14 days
- D13.8 days
Show answer & explanationAnswer & explanation
Correct answer: A. 13.4 days
To find the mean, sum all the values and divide by the number of values. (12 + 15 + 10 + 18 + 12) / 5 = 67 / 5 = 13.4 days.
Why the other options are wrong
- B. This is the mode, not the mean.
- C. This calculation is incorrect.
- D. This calculation is incorrect.
Mean (Average)
The sum of all values in a dataset divided by the number of values in the dataset.
- Most common measure of central tendency.
- Sensitive to outliers.
- Represents the 'balancing point' of the data.
Memory trick: Central tendency: mean is sum, median is middle, mode is most.