Math Problem Statement

The following scores were achieved by students on a statisties test: 82, 93,26, 56, 75 73, 80, 61, 79, 90, 94, 93, 100, 71, 100, 60. Compute the mean and the median for these data and explain why they are different.

Solution

Let's start by computing the mean and the median for the given set of data:

Data:

82, 93, 26, 56, 75, 73, 80, 61, 79, 90, 94, 93, 100, 71, 100, 60

Step 1: Mean

The mean (or average) is the sum of all the numbers divided by the total number of values.

Formula for the mean:

Mean=All scoresNumber of scores\text{Mean} = \frac{\sum \text{All scores}}{\text{Number of scores}}

Let's calculate the sum of the data: 82+93+26+56+75+73+80+61+79+90+94+93+100+71+100+60=102382 + 93 + 26 + 56 + 75 + 73 + 80 + 61 + 79 + 90 + 94 + 93 + 100 + 71 + 100 + 60 = 1023

Now, count the number of data points: Number of scores=16\text{Number of scores} = 16

Now, calculate the mean: Mean=102316=63.9375\text{Mean} = \frac{1023}{16} = 63.9375

So, the mean is approximately 63.94.

Step 2: Median

The median is the middle number in a data set when the numbers are arranged in ascending order. If there is an even number of data points, the median is the average of the two middle values.

Step 2.1: Arrange the data in ascending order:

26, 56, 60, 61, 71, 73, 75, 79, 80, 82, 90, 93, 93, 94, 100, 100

Step 2.2: Find the middle values

Since we have 16 data points (an even number), the median will be the average of the 8th and 9th values in the ordered list.

The 8th and 9th values are:

  • 8th value: 79
  • 9th value: 80

Now, calculate the median: Median=79+802=1592=79.5\text{Median} = \frac{79 + 80}{2} = \frac{159}{2} = 79.5

So, the median is 79.5.

Step 3: Why are the mean and median different?

The mean and median are different because the data set is skewed by the extreme values at the higher end (the two 100s). These high values push the mean higher than the median. In contrast, the median is less affected by extreme values and more reflective of the central position of the data.

Summary:

  • Mean: 63.94
  • Median: 79.5

Would you like any further details or have any questions?

Here are some related questions to explore:

  1. What is the effect of outliers on the mean and median?
  2. How would the mean and median change if the highest score (100) were removed?
  3. What is the mode of this data set?
  4. How do you calculate the range of a data set?
  5. How can the standard deviation help in understanding data dispersion?

Tip: Always consider both the mean and median when analyzing data, especially if there are outliers, as they can tell you different stories about the distribution.

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Math Problem Analysis

Mathematical Concepts

Statistics
Mean
Median
Data Analysis

Formulas

Mean = (Sum of all scores) / (Number of scores)
Median = Middle value when data is ordered (or average of two middle values for even data sets)

Theorems

Central Tendency
Effect of Skewed Data on Mean and Median

Suitable Grade Level

Grades 6-9