Solve a problem

Descriptive statisticsStatistics and probabilityMiddle schoolabout 1:02

Average of 90, 85, 77: animated lesson

A narrated, step-by-step descriptive statistics video lesson with captions. Final answer: Mean = 84; Median = 85; Mode = no mode; Range = 13.

SpeedLanguage

Chapters

Transcript

Video with a synthetic English voice and captions. Pick another language for subtitles in that language, or open the interactive version.

Video narrated by a synthetic voice (Piper TTS, en_US-ljspeech-high voice (LJ Speech dataset, public domain)); the steps come from our maths engine and the answer was checked independently. Download MP4 (0.4 MB) · Captions (WebVTT)

Steps on screen

1. The problem
Mean, median and mode
Data: 90, 85, 77
2. Steps, part 1
1. $77, 85, 90\quad (n = 3)$
  Sort the data from smallest to largest
2. $\bar{x} = \frac{252}{3} = 84$
  Mean: add the values and divide by how many there are
3. $\text{median} = 85$
  Median: the middle value of the sorted list
4. Mode: the value(s) that appear most often
3. Steps, part 2
1. $90 - 77 = 13$
  Range: largest minus smallest
4. The answer
$\text{Mean = 84; Median = 85; Mode = no mode; Range = 13}$
mean 84, median 85, mode no mode, range 13
5. Check
- Sum 252 = mean × n = 84 × 3 = 252

Transcript

The problem. Here is the problem: Data: 90, 85, 77. Measures of central tendency for a list of numbers.

Steps, part 1. Sort the data from smallest to largest. Mean: add the values and divide by how many there are. Median: the middle value of the sorted list. With 3 values (odd), the median is value number 2. Mode: the value(s) that appear most often. Every value appears exactly once, so there is no mode.

Steps, part 2. Range: largest minus smallest.

The answer. So the answer is Mean equals 84; Median equals 85; Mode equals no mode; Range equals 13. The mean balances all values, the median splits the sorted data in half and is less affected by outliers, and the mode is the most common value.

Check. Sum 252 equals mean times n equals 84 times 3 equals 252.

About descriptive statistics

Mean, median, mode, range, variance and standard deviation of a data set.

Average of 90, 85, 77: Animated Step-by-Step Lesson