Table of contents
- 1. Intro to Stats and Collecting Data24m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically53m
- 4. Probability1h 29m
- 5. Binomial Distribution & Discrete Random Variables1h 16m
- 6. Normal Distribution and Continuous Random Variables58m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 5m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
3. Describing Data Numerically
Median
Problem 3.1.11
Textbook Question
Critical Thinking. For Exercises 5–20, watch out for these little buggers. Each of these exercises involves some feature that is somewhat tricky. Find the (a) mean, (b) median, (c) mode, (d) midrange, and then answer the given question.
Smart Thermostats Listed below are selling prices (dollars) of smart thermostats tested by Consumer Reports magazine. If you decide to buy one of these smart thermostats, what statistic is most relevant, other than the measures of central tendency?
250 170 225 100 250 250 130 200 150 250 170 200 180 250

1
Step 1: Organize the data set. Begin by listing all the selling prices in ascending order to make calculations easier. The sorted data set is: 100, 130, 150, 170, 170, 180, 200, 200, 225, 250, 250, 250, 250, 250.
Step 2: Calculate the mean. The mean is the average of the data set. Use the formula: <math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mrow><mo>∑</mo><mi>x</mi></mrow><mi>n</mi></mfrac></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML"><mo>∑</mo><mi>x</mi></math> is the sum of all data points and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>n</mi></math> is the number of data points.
Step 3: Calculate the median. The median is the middle value when the data set is ordered. If the number of data points is odd, the median is the middle value. If even, it is the average of the two middle values. Identify the middle values in the sorted data set and compute accordingly.
Step 4: Determine the mode. The mode is the value that appears most frequently in the data set. Count the frequency of each value in the sorted data set and identify the value(s) with the highest frequency.
Step 5: Calculate the midrange. The midrange is the average of the minimum and maximum values in the data set. Use the formula: <math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mrow><mo>(</mo><mi>min</mi><mo>+</mo><mi>max</mi><mo>)</mo></mrow><mn>2</mn></mfrac></math>. Then, consider the question about the most relevant statistic other than measures of central tendency. Reflect on variability measures like range or standard deviation, which provide insights into the spread of the data.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Measures of Central Tendency
Measures of central tendency, including the mean, median, and mode, summarize a set of data by identifying the central point within that dataset. The mean is the average value, the median is the middle value when data is ordered, and the mode is the most frequently occurring value. Understanding these measures helps in interpreting data distributions and making informed decisions based on typical values.
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Variability
Variability refers to how spread out or dispersed the values in a dataset are. Common measures of variability include range, variance, and standard deviation. Analyzing variability is crucial because it provides insight into the consistency of the data and helps identify potential outliers, which can significantly affect the interpretation of central tendency measures.
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Contextual Relevance of Statistics
The relevance of a statistic depends on the context in which it is applied. In the case of purchasing smart thermostats, factors such as price range, consumer reviews, and energy efficiency may be more pertinent than just the average price. Understanding the context allows for a more comprehensive analysis and better decision-making based on the data presented.
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