Math Problem Statement

or the data shown, answer the questions. Round to 2 decimal places.

x 14.8 15.7 25.6 22.1 12.9

Find the mean:

Find the median:

Find the sample standard deviation:

Solution

To solve this, we calculate the mean, median, and sample standard deviation of the given dataset. The steps are as follows:

Data:

x = [14.8, 15.7, 25.6, 22.1, 12.9]


1. Mean:

The formula for the mean is:

Mean=xin\text{Mean} = \frac{\sum x_i}{n}

Mean=14.8+15.7+25.6+22.1+12.95=91.15=18.22\text{Mean} = \frac{14.8 + 15.7 + 25.6 + 22.1 + 12.9}{5} = \frac{91.1}{5} = 18.22


2. Median:

To find the median, arrange the data in ascending order:

[12.9,14.8,15.7,22.1,25.6][12.9, 14.8, 15.7, 22.1, 25.6]

Since there is an odd number of data points (n=5n=5), the median is the middle value:

Median=15.7\text{Median} = 15.7


3. Sample Standard Deviation:

The formula for sample standard deviation is:

s=(xixˉ)2n1s = \sqrt{\frac{\sum (x_i - \bar{x})^2}{n-1}}

Steps:

  1. Compute the deviations (xixˉ)(x_i - \bar{x}), where xˉ=18.22\bar{x} = 18.22.
  2. Square the deviations (xixˉ)2(x_i - \bar{x})^2.
  3. Sum the squared deviations.
  4. Divide by n1n-1, where n=5n=5.
  5. Take the square root.

s=(14.818.22)2+(15.718.22)2+(25.618.22)2+(22.118.22)2+(12.918.22)251s = \sqrt{\frac{(14.8 - 18.22)^2 + (15.7 - 18.22)^2 + (25.6 - 18.22)^2 + (22.1 - 18.22)^2 + (12.9 - 18.22)^2}{5-1}}

s=(3.42)2+(2.52)2+(7.38)2+(3.88)2+(5.32)24s = \sqrt{\frac{(-3.42)^2 + (-2.52)^2 + (7.38)^2 + (3.88)^2 + (-5.32)^2}{4}}

s=11.70+6.35+54.46+15.05+28.304s = \sqrt{\frac{11.70 + 6.35 + 54.46 + 15.05 + 28.30}{4}}

s=115.864=28.96=5.38s = \sqrt{\frac{115.86}{4}} = \sqrt{28.96} = 5.38


Final Answers:

  1. Mean: 18.2218.22
  2. Median: 15.715.7
  3. Sample Standard Deviation: 5.385.38

Let me know if you want further explanations!


Related Questions:

  1. How do you interpret the mean in this context?
  2. What is the significance of the median for skewed datasets?
  3. How does standard deviation measure data spread?
  4. What would change in calculations if it were a population standard deviation?
  5. How would adding an extra value affect the mean and standard deviation?

Tip:

Always organize data in ascending order for median calculations and recheck arithmetic steps for accuracy.

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Math Problem Analysis

Mathematical Concepts

Statistics
Mean
Median
Standard Deviation

Formulas

Mean = (Σx) / n
Median = Middle value in an ordered dataset
Sample Standard Deviation = sqrt((Σ(xi - x̄)^2) / (n - 1))

Theorems

Properties of arithmetic mean
Properties of central tendency
Concept of dispersion in statistics

Suitable Grade Level

Grades 9-12