- What's the difference between cumulative TRUE and FALSE in NORM.DIST?
- cumulative=TRUE returns the cumulative distribution function (CDF): the probability that a random value is at or below x, ranging from 0 to 1. cumulative=FALSE returns the probability density function (PDF): the height of the normal curve at x, which is rarely used directly but needed for charting the distribution curve.
- How do I find the probability a value falls between two numbers?
- Use two NORM.DIST calls with cumulative=TRUE and subtract them: =NORM.DIST(upper_limit, mean, stdev, TRUE) − NORM.DIST(lower_limit, mean, stdev, TRUE). This gives you the probability of any value falling between those two boundaries.
- What if my budget data doesn't look like a normal distribution?
- NORM.DIST assumes a perfect bell curve, so it will give inaccurate results for skewed or multi-peaked data. Verify your data is roughly normal before relying on NORM.DIST. For other distribution shapes, consider MEDIAN or MODE.SNGL, or apply data transformations before calculating.
- Can NORM.DIST predict my future budget overruns?
- No. NORM.DIST calculates probabilities within a historical distribution—it answers 'how likely is this value given past data?' but does not forecast trends, inflation, or external changes. Use it for understanding historical patterns, not for predictive budgeting alone.