Grade 9 Math: Understanding Variance
This worksheet focuses on understanding and calculating variance for grade 9 students, covering definitions, formulas, and practical applications.
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Grade 9 Math: Understanding Variance
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Read each question carefully and answer to the best of your ability. Show all your work for calculation problems.
1. Which of the following best describes variance?
The average value of a dataset
A measure of the spread of data points around the mean
The middle value in a dataset
The most frequent value in a dataset
2. What is the symbol commonly used to represent population variance?
σ
s²
μ
x̄
1. Variance is calculated by taking the average of the from the mean.
2. The square root of the variance is known as the .
3. A high variance indicates that data points are from the mean, while a low variance indicates they are to the mean.
1. Explain why we square the differences from the mean when calculating variance.
2. What is the main difference between population variance and sample variance?
1. Variance can never be a negative value.
True
False
2. Standard deviation is always smaller than variance.
True
False
Calculate the variance for the following dataset:
Dataset: {2, 4, 6, 8, 10}
The bar graph below shows the number of hours students spent studying for a test. Calculate the variance of the study hours.