Math Problem Statement

A cellular phone company monitors monthly phone usage. The following data represent the monthly phone use in minutes of one particular customer for the past 20 months. Use the given data to answer parts​ (a) and​ (b)

var1 339 484 524 548 517 403 551 387 487 466 418 448 453 553 424 414 454 485 405 462 Determine the standard deviation and interquartile range of the data. sequals    enter your response here ​(Round to two decimal places as​ needed.)

Solution

To calculate the standard deviation and the interquartile range (IQR) of the given data, we will follow these steps:

Step 1: Organize the data

The given data is:

339,484,524,548,517,403,551,387,487,466,418,448,453,553,424,414,454,485,405,462339, 484, 524, 548, 517, 403, 551, 387, 487, 466, 418, 448, 453, 553, 424, 414, 454, 485, 405, 462

Step 2: Standard Deviation Calculation

The formula for the standard deviation ss is:

s=1n1i=1n(xixˉ)2s = \sqrt{\frac{1}{n-1} \sum_{i=1}^{n} (x_i - \bar{x})^2} Where:

  • nn is the number of data points
  • xˉ\bar{x} is the mean (average) of the data points
  • xix_i represents each data point

Step 3: Interquartile Range (IQR) Calculation

The IQR is the difference between the third quartile (Q3) and the first quartile (Q1): IQR=Q3Q1IQR = Q3 - Q1

Let me perform these calculations for you.The standard deviation of the data is approximately 58.77 and the interquartile range (IQR) is 77.5.

Would you like a more detailed explanation or any additional information on this? Here are 5 related questions:

  1. How is the standard deviation used to measure data variability?
  2. What are quartiles, and how do they relate to the interquartile range?
  3. How can we interpret the interquartile range in practical scenarios?
  4. How is the sample standard deviation different from population standard deviation?
  5. Can outliers significantly affect the standard deviation and IQR?

Tip: The standard deviation provides a measure of spread, while the interquartile range focuses on the middle 50% of the data, making it more resistant to outliers.

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Math Problem Analysis

Mathematical Concepts

Descriptive Statistics
Data Analysis
Measures of Spread

Formulas

Standard Deviation formula: s = sqrt((1/(n-1)) * Σ(xi - x̄)^2)
Interquartile Range formula: IQR = Q3 - Q1

Theorems

Empirical Rule (Standard Deviation)

Suitable Grade Level

Grades 9-12