Mean, median and mode

• What should you be able to calculate by the end of the video?

  Mean, median, and mode
• Why do students panic at the thought of maths?

  They believe it is difficult
• How do you calculate the mean of a set of values?

  Add all numbers and divide by count
• What is the mean value of the heights 5, 4, 7, 6, and 5?

  5.4 centimeters
• What is an anomalous result?

  A result that does not fit the pattern
• How do you calculate the mean without an anomalous result?

  Add remaining numbers and divide by their count
• What is the mean value of the masses 11, 13, 21, 10, and 8 without the anomalous result?

  10.5 grams
• What is the median of a set of numbers?

  The middle value of the ordered numbers
• How do you find the median of the numbers 4, 8, 4, 7, 6, 3, and 8?

  Order them and select the middle number
• What is the median value of the ordered numbers 3, 4, 4, 6, 7, 8, and 8?

  6
• How do you find the median in an even set of numbers?

  Take the mean of the two central numbers
• What is the median of the numbers 2, 5, 6, 6, 7, 7, 7, 9, and 10?


  7
• What is the mode of a set of numbers?

  The number that appears most often
• What is the mode of the numbers 2, 5, 6, 6, 7, 7, 7, 9, and 10?


  7
• What happens if no number appears most often in a set?

  There cannot be a mode
• What are the three measures of central tendency that can be calculated for a set of values?

  Mean, median, mode
• How do you calculate the mean of a set of values?

  Add all the values and divide by the number of values
• A student measured the height in centimeters of 5 plants as 5, 4, 7, 6, and 5. What is the mean height?

  5.4 cm
• What is an anomalous result?

  A value that does not fit the pattern of the other values
• A student measured the mass in grams of 5 earthworms as 11, 13, 21, 10, and 8. What is the mean mass excluding the anomalous result?

  10.5 g
• How do you calculate the median of a set of values?

  Arrange the values in order and select the middle value
• A scientist counted the number of eggs laid by 7 different birds as 4, 8, 4, 7, 6, 3, and 8. What is the median number of eggs?

  6
• What is the mode of a set of values?

  The value that appears most often
• A scientist counted the number of daisies in 9 different quadrats as 2, 5, 6, 6, 7, 7, 7, 9, and 10. What is the mode?


  7
• What happens if there is no single number that appears most often in a set of values?

  There is no mode
• What are the key differences between the mean, median, and mode?

  • Mean: The average, calculated by adding all values and dividing by the number of values
  • Median: The middle value when the values are arranged in order
  • Mode: The value that appears most often
• When would you use each measure of central tendency (mean, median, mode)?

  • Mean: Good for representing the "typical" value, but can be skewed by outliers
  • Median: Good for skewed distributions, resistant to outliers
  • Mode: Good for identifying the most common value, useful for categorical data
• What are the strengths and weaknesses of using the mean, median, and mode?

  Strengths:

  • Mean: Gives an overall average
  • Median: Robust to outliers
  • Mode: Identifies most common value

  
  

  Weaknesses:

  • Mean: Sensitive to outliers
  • Median: Does not use all data points
  • Mode: May not represent "typical" value