1. What is Z-Score?

The Z-score, also known as the standard score, is a statistical measurement that describes a value's relationship to the mean of a group of values. For a 95% service level, the Z-score is 1.645, representing the number of standard deviations from the mean.

2. How Does the Calculator Work?

The calculator provides the Z-score value for a 95% service level:

This value is fixed for a 95% service level in a one-tailed normal distribution.

3. Importance of Z-Score in Service Level

Details: Z-score is crucial in inventory management and service level calculations. It helps determine safety stock levels and reorder points to maintain desired service levels.

4. Using the Calculator

Tips: This calculator specifically provides the Z-score for a 95% service level. Simply click the calculate button to get the value.

5. Frequently Asked Questions (FAQ)

Q1: Why is the Z-score 1.645 for 95% service level?
A: In a standard normal distribution, 95% of the area under the curve falls below Z = 1.645 in a one-tailed test.

Q2: Can I calculate Z-scores for other service levels?
A: Yes, but this calculator is specifically designed for the 95% service level. Other service levels would require different Z-score values.

Q3: How is Z-score used in inventory management?
A: Z-score is used to calculate safety stock: Safety Stock = Z × σ × √(Lead Time), where σ is the standard deviation of demand.

Q4: What's the difference between one-tailed and two-tailed Z-scores?
A: Service level calculations typically use one-tailed Z-scores as we're interested in the probability of not exceeding a certain value (stockout).

Q5: Is the Z-score the same for all normal distributions?
A: Yes, Z-scores are standardized and apply to all normal distributions, regardless of their mean or standard deviation.