Daily DAX : Day 391 NORM.S.DIST

NORM.S.DIST Function in Power BI DAX

Function Syntax

NORM.S.DIST(z, cumulative)

Parameters

Parameter Description
z The value for which you want the distribution (z-score). Must be a numeric value.
cumulative A logical value (TRUE/FALSE):
• TRUE = Returns the cumulative distribution function (CDF)
• FALSE = Returns the probability density function (PDF)

What It Returns

  • If cumulative = TRUE: Probability that a standard normal random variable is ≤ z
  • If cumulative = FALSE: Height of the standard normal curve at point z

Example 1: Cumulative Probability (CDF)

NORM.S.DIST(1.96, TRUE)

Result: ≈ 0.975

Meaning: 97.5% of the data in a standard normal distribution lies below a z-score of 1.96.

Example 2: Probability Density (PDF)

NORM.S.DIST(0, FALSE)

Result: ≈ 0.3989

Meaning: The peak of the standard normal curve at z = 0 is about 0.4.

Use Cases in Power BI

  • Statistical Analysis: Calculate p-values or confidence intervals from z-scores.
  • Quality Control: Determine how many standard deviations a measurement is from the mean (e.g., Six Sigma dashboards).
  • Risk Assessment: Model probabilities in financial or operational risk metrics using z-scores.
  • Dynamic Thresholds: Flag outliers — e.g., show values where NORM.S.DIST(z, TRUE) > 0.95 as "top 5% performers".

Note: This function assumes a standard normal distribution (mean = 0, standard deviation = 1). For non-standard normal distributions, use NORM.DIST instead.

Practical Example in Power BI

Suppose you have a column of z-scores in a table called SalesData:

P-Value = NORM.S.DIST([Z-Score], TRUE)
Probability Density = NORM.S.DIST([Z-Score], FALSE)

You can create a measure to identify extreme values:

Is Outlier (95% Confidence) = 
IF(
    NORM.S.DIST(ABS([Z-Score]), TRUE) > 0.975,
    "Yes",
    "No"
)

Comments

Post a Comment

Popular posts from this blog

Daily DAX : Day 131 SELECTEDMEASURE

 The SELECTEDMEASURE function in Power BI's DAX (Data Analysis Expressions) language is a powerful tool used primarily within calculation groups to dynamically reference the measure currently being evaluated in a report. It’s part of the calculation group feature introduced to streamline complex reporting scenarios and improve maintainability by reducing the need to duplicate measure logic. What is SELECTEDMEASURE? SELECTEDMEASURE is a DAX function that returns a reference to the measure that is currently active or "selected" in the context of a calculation group. It doesn’t take any arguments and is typically used in the expression of a calculation item within a calculation group. This allows you to write generic logic that can dynamically apply to whichever measure is being evaluated in a visual, without hardcoding specific measure names. Syntax SELECTEDMEASURE()     Returns: A reference to the measure currently being evaluated in the report context. Use Case SELECTEDME...
Read more

Daily DAX : Day 446 INFO.CSDLMETADATA

Power BI DAX Function: INFO.CSDLMETADATA INFO.CSDLMETADATA` is a specialized DAX function introduced as part of a broader set of "INFO" functions (like `INFO.TABLES` or `INFO.MEASURES`) used for **model introspection**. It allows you to programmatically access the underlying structure of your Power BI semantic model. What does it do? The function returns a table with a single column containing the Conceptual Schema Definition Language (CSDL)  metadata of your model in XML format . In plain English, it exports a highly technical "blueprint" of your entire data model—including tables, columns, relationships, and measures—as a structured XML string. It is essentially the DAX equivalent of the `DISCOVER_CSDL_METADATA` Dynamic Management View (DMV) used in Analysis Services. --- Syntax and Output The syntax is straightforward as it requires no arguments: ```dax EVALUATE INFO.CSDLMETADATA() ``` Return Value : A table with one column and one row. Content : A long string ...
Read more

Daily DAX : Day 453 ENDOFWEEK

Power BI DAX Function: ENDOFWEEK Description The ENDOFWEEK function is a Time Intelligence function in DAX (Data Analysis Expressions) used in Power BI. It returns the date that represents the end of the week containing a specified date (typically Saturday, as weeks are considered to start on Sunday by default in DAX time intelligence). Syntax ENDOFWEEK( [, ]) : A column reference (usually from a Date table) or a date expression. Required. : Optional. Specifies the week-ending convention. Default is Saturday if omitted. Examples 1. Basic usage (default: week ends on Saturday): End of Week = ENDOFWEEK('Date'[Date]) For a date like January 8, 2026 (Thursday), this would return January 10, 2026 (Saturday). 2. In a measure for cumulative sales up to end of week: Total Sales to End of Week = CALCULATE( SUM(Sales[Amount]), DATESBETWEEN('Date'[Date], ST...
Read more