Math Problem Statement

if the variance of a dataset is 50 and all data points are incresases by 100% then what will be the variance

Solution

To solve this problem, let's first understand what happens to the variance when all data points in a dataset are increased by a certain percentage.

Understanding the Impact on Variance

  1. Variance Definition: The variance of a dataset is a measure of the spread of the data points around the mean. It is defined as the average of the squared differences from the mean.

  2. Scaling Data Points: If each data point in a dataset is scaled by a factor kk, the new variance Var(kX)\text{Var}(kX) of the dataset will be k2×Var(X)k^2 \times \text{Var}(X). This is because variance is affected by the square of the scaling factor.

  3. Applying the Scaling to the Problem:

    • In this case, each data point is increased by 100%.
    • Increasing a data point by 100% means multiplying it by 2 (since 1+100%=1+1=21 + 100\% = 1 + 1 = 2).
  4. Calculating the New Variance:

    • Original variance, Var(X)=50\text{Var}(X) = 50.
    • Scaling factor, k=2k = 2.
    • The new variance will be Var(2X)=22×Var(X)\text{Var}(2X) = 2^2 \times \text{Var}(X).

New Variance=22×50=4×50=200\text{New Variance} = 2^2 \times 50 = 4 \times 50 = 200

Conclusion

If all data points in a dataset are increased by 100%, the variance of the dataset will increase by a factor of 4. Therefore, the new variance will be 200.

Would you like more details or have any questions?

Here are some related questions you might find interesting:

  1. What happens to the standard deviation when all data points are increased by 100%?
  2. How does adding a constant to all data points affect the variance?
  3. What is the difference between variance and standard deviation?
  4. If the original dataset had a mean of 10, what would the new mean be after increasing each data point by 100%?
  5. How is variance affected if all data points are multiplied by a negative number?

Tip: Remember that variance is sensitive to changes in data scale but not to shifts (adding or subtracting a constant).

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Math Problem Analysis

Mathematical Concepts

Variance
Scaling of Data
Statistical Measures

Formulas

Variance formula: Var(X) = E[(X - μ)^2]

Theorems

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Suitable Grade Level

Advanced High School / College