Math Problem Statement

A flourmill is concerned that new machinery is not filling bags correctly. The bags are supposed to have a population mean weight of 500 grams. A random sample of 147 bags of flour has a mean weight of 541 grams and a standard deviation of 3.3 grams. Give the value of the calculated test statistic, to two decimal places

Solution

To calculate the test statistic for this situation, we will use the formula for the Z-test when the population standard deviation is unknown, but a sample standard deviation is given:

Z=XˉμsnZ = \frac{\bar{X} - \mu}{\frac{s}{\sqrt{n}}}

Where:

  • Xˉ\bar{X} is the sample mean (541 grams),
  • μ\mu is the population mean (500 grams),
  • ss is the sample standard deviation (3.3 grams),
  • nn is the sample size (147 bags).

Let's calculate the test statistic.The value of the calculated test statistic is 150.64.

Would you like more details or have any questions about this? Here are some related questions to expand your understanding:

  1. How do you interpret the result of the Z-test in this context?
  2. What is the significance of using a Z-test over a t-test here?
  3. How would you determine if the machinery is significantly overfilling the bags?
  4. What is the critical Z-value for a 95% confidence level in a one-tailed test?
  5. How would increasing the sample size affect the test statistic?

Tip: A large test statistic like this indicates a significant difference between the sample mean and the population mean.

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Math Problem Analysis

Mathematical Concepts

Statistics
Z-Test
Hypothesis Testing

Formulas

Z = (X̄ - μ) / (s / √n)

Theorems

Central Limit Theorem
Z-Distribution

Suitable Grade Level

College/University