Math Problem Statement
The table below sows the number of hate crimes for 2007 to 2018. The value for 2007 is slightly different than the actual value so that each student gets their own unique problem.
Year
Number of hate crimes
2007
7635
2008
7783
2009
6604
2010
6628
2011
6222
2012
5796
2013
5928
2014
5479
2015
5850
2016
6121
2017
7175
2018
7120
Here is the data so you can copy and paste special it into the raw data sheet.
Number of hate crimes
7635
7783
6604
6628
6222
5796
5928
5479
5850
6121
7175
7120
- You can see the graph of the actual data points at this site here. What type of distribution do you think this is?
Normal distribution
Skewed right
Skewed left
Flat distribution
-
What is the mean?
-
What is the population standard deviation?
Solution
Let's work through this step by step.
1. Distribution Type:
Looking at the data, the number of hate crimes fluctuates across the years. The data starts high in 2007, decreases in the middle years, and rises again towards 2017–2018. This distribution likely appears to have a skewed left pattern because the values decrease more dramatically in the middle years and rise again, leaving a longer left tail.
2. Mean:
The mean () is the average of the values, calculated by summing the total number of hate crimes and dividing by the number of years.
Hate Crime Data:
First, sum these values:
Next, divide by the number of data points (12 years):
So, the mean number of hate crimes is approximately 6778.42.
3. Population Standard Deviation:
The population standard deviation () measures the spread of data points. The formula for population standard deviation is:
Where:
- are the individual data points,
- is the mean,
- is the total number of data points (12 in this case).
Step-by-Step Calculation:
- Subtract the mean from each data point and square the result.
- Sum these squared differences.
- Divide by the total number of data points (since it's a population standard deviation).
- Take the square root of the result.
I'll calculate this next.### 2. Mean: The calculated mean number of hate crimes from 2007 to 2018 is approximately 6528.42.
3. Population Standard Deviation:
The population standard deviation is approximately 724.60.
Would you like further details on any of these calculations or the method used?
Here are 5 follow-up questions that you might find interesting:
- How does the standard deviation help us understand the data spread?
- What does the skewness of the data indicate about changes in hate crimes over time?
- Could we fit a trend line to the data, and what type of model might fit best?
- How could the median be helpful in this context compared to the mean?
- How would you compare the standard deviation with the variance?
Tip: When interpreting a distribution, always look at both the skewness and the mean to get a clear picture of how data points are spread.
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Math Problem Analysis
Mathematical Concepts
Descriptive Statistics
Mean
Standard Deviation
Data Distribution
Formulas
Mean: μ = Σx / N
Population Standard Deviation: σ = sqrt(Σ(xᵢ - μ)² / N)
Theorems
Measures of Central Tendency
Measures of Dispersion
Suitable Grade Level
Grades 10-12
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