Math Problem Statement

Listed below are the numbers of hurricanes that occurred in each year in a certain region. The data are listed in order by year. Find the​ range, variance, and standard deviation for the given sample data. Include appropriate units in the results. What important feature of the data is not revealed by any of the measures of​ variation?

2020

1616

22

11

1313

66

1010   2020

1414

1717

55

1313

2020

1616

Question content area bottom

Part 1

The range of the sample data is

enter your response here

▼   hurricanes squared .hurricanes2.

years.years.

years squared .years2.

hurricanes.hurricanes.

​(Round to one decimal place as​ needed.)

Solution

Let's break down the problem into parts.

Sample Data:

  • 20, 16, 22, 11, 13, 6, 10, 20, 14, 17, 5, 13, 20, 16

Part 1: Range

The range is the difference between the largest and smallest values in the data.

  1. The maximum value is 22.
  2. The minimum value is 5.

Range=225=17 hurricanes\text{Range} = 22 - 5 = 17 \text{ hurricanes}

Part 2: Variance

The variance measures how much the data values vary from the mean.

  1. Calculate the mean: Mean=Data ValuesNumber of Data Points\text{Mean} = \frac{\sum \text{Data Values}}{\text{Number of Data Points}} The sum of the data values is: 20+16+22+11+13+6+10+20+14+17+5+13+20+16=20320 + 16 + 22 + 11 + 13 + 6 + 10 + 20 + 14 + 17 + 5 + 13 + 20 + 16 = 203 There are 14 data points: Mean=2031414.5\text{Mean} = \frac{203}{14} \approx 14.5

  2. Calculate the squared deviations from the mean: For each data point xix_i, calculate (ximean)2(x_i - \text{mean})^2.

  3. Variance formula: Variance=(ximean)2n1\text{Variance} = \frac{\sum (x_i - \text{mean})^2}{n - 1}

Let me now calculate the variance and standard deviation for this data.### Results:

  • Range: 17hurricanes17 \, \text{hurricanes}
  • Mean: 14.5hurricanes14.5 \, \text{hurricanes}
  • Variance: 27.5hurricanes227.5 \, \text{hurricanes}^2
  • Standard Deviation: 5.2hurricanes5.2 \, \text{hurricanes} (rounded to one decimal place)

Important Feature Not Revealed by Variation Measures:

None of these measures—range, variance, or standard deviation—provide any information about the distribution shape of the data, such as whether it is skewed, symmetric, or has any outliers.

Would you like further clarification or details on any step?

Here are 5 related questions to consider:

  1. How would the range change if an extreme value (e.g., 30) were added?
  2. What is the difference between population variance and sample variance?
  3. How would you calculate the variance for a population instead of a sample?
  4. What does a high standard deviation imply about the dataset?
  5. How would the variance change if all values in the dataset were the same?

Tip: The standard deviation is a useful measure of spread but can be sensitive to outliers in the data.

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Math Problem Analysis

Mathematical Concepts

Statistics
Measures of Variation
Range
Variance
Standard Deviation

Formulas

Range = max(data) - min(data)
Variance = Σ(x_i - mean)^2 / (n - 1)
Standard Deviation = √Variance

Theorems

Empirical Rule
Chebyshev's Theorem

Suitable Grade Level

Grades 10-12