Math Problem Statement

The table below gives the number of hours spent watching TV last week by a sample of 24 children.

4 10 7 6 2 3 4 10 7 4 1 1 7 3 3 1 9 7 4 7 1 9 8 4

Range =

(Please enter an exact answer.)

Sample Standard Deviation = (Please show your answer to 4 decimal places.)

Solution

To solve for the range and the sample standard deviation, we proceed as follows:


1. Range

The range is calculated as:

Range=Maximum valueMinimum value\text{Range} = \text{Maximum value} - \text{Minimum value}

From the data, the maximum value is 1010 and the minimum value is 11.

Range=101=9\text{Range} = 10 - 1 = 9


2. Sample Standard Deviation

The formula for the sample standard deviation is:

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

Where:

  • xix_i are the data points,
  • xˉ\bar{x} is the sample mean,
  • nn is the number of data points.

Step 1: Find the Mean (xˉ\bar{x})

Sum all the values:

Sum=4+10+7+6+2+3+4+10+7+4+1+1+7+3+3+1+9+7+4+7+1+9+8+4\text{Sum} = 4 + 10 + 7 + 6 + 2 + 3 + 4 + 10 + 7 + 4 + 1 + 1 + 7 + 3 + 3 + 1 + 9 + 7 + 4 + 7 + 1 + 9 + 8 + 4

Sum=124\text{Sum} = 124

Number of values (nn) is 2424, so the mean is:

xˉ=Sumn=124245.1667\bar{x} = \frac{\text{Sum}}{n} = \frac{124}{24} \approx 5.1667

Step 2: Compute (xixˉ)2(x_i - \bar{x})^2

For each data point xix_i, calculate the squared deviation from the mean. The values are:

xi:{4,10,7,6,2,3,4,10,7,4,1,1,7,3,3,1,9,7,4,7,1,9,8,4}x_i: \{4, 10, 7, 6, 2, 3, 4, 10, 7, 4, 1, 1, 7, 3, 3, 1, 9, 7, 4, 7, 1, 9, 8, 4\}

Let me calculate this systematically.import numpy as np

Data points

data = [4, 10, 7, 6, 2, 3, 4, 10, 7, 4, 1, 1, 7, 3, 3, 1, 9, 7, 4, 7, 1, 9, 8, 4]

Number of data points (n)

n = len(data)

Mean

mean = np.mean(data)

Deviations squared

squared_deviations = [(x - mean) ** 2 for x in data]

Sample variance

sample_variance = sum(squared_deviations) / (n - 1)

Sample standard deviation

sample_std_dev = np.sqrt(sample_variance)

mean, sample_std_dev(5.083333333333333, 2.962323803847341)(5.083333333333333, 2.962323803847341)successThe mean (xˉ\bar{x}) of the data is approximately 5.08335.0833.

The sample standard deviation is:

s2.9623s \approx 2.9623


Final Results

  1. Range = 99
  2. Sample Standard Deviation = 2.96232.9623 (rounded to 4 decimal places)

Let me know if you'd like the step-by-step squared deviation calculations or have further questions!


Related Questions:

  1. How is the range influenced by outliers in a dataset?
  2. What does the standard deviation tell us about the variability of the data?
  3. How does the sample standard deviation differ from the population standard deviation?
  4. Can you calculate the variance and interpret its significance here?
  5. What happens to the mean and standard deviation if an extreme outlier is added?

Tip: Always verify data entry carefully when calculating statistics to avoid errors in large datasets!

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Math Problem Analysis

Mathematical Concepts

Descriptive Statistics
Range
Sample Standard Deviation
Mean

Formulas

Range = Maximum value - Minimum value
Sample Standard Deviation = sqrt(Sum of squared deviations / (n - 1))
Mean = Sum of data values / Number of data values

Theorems

Standard Deviation formula in descriptive statistics

Suitable Grade Level

Grades 9-12