T.DIST Function in Excel: Student’s t Probability
T.DIST gives probabilities for the t-distribution — used instead of the normal curve when samples are small.
Read article →FORECAST.ETS.SEASONALITY Function in Excel: Which Cycle Did Excel Find?
FORECAST.ETS.SEASONALITY Function in Excel: Which Cycle Did Excel Find?
FORECAST.ETS.SEASONALITY reports the season length Excel detected — 12 for a yearly cycle in monthly data, 7 for a weekly cycle in daily data.
Read article →FORECAST.ETS.CONFINT Function in Excel: How Uncertain Is the Forecast?
FORECAST.ETS.CONFINT Function in Excel: How Uncertain Is the Forecast?
FORECAST.ETS.CONFINT returns the ± interval around a FORECAST.ETS value. A forecast of 1,200 ± 400 tells a very different story from 1,200 ± 40.
Read article →STEYX Function in Excel: Typical Error of a Trend Line
STEYX Function in Excel: Typical Error of a Trend Line
STEYX returns the standard error of predicted y values — roughly how far actual points sit from the trend line.
Read article →LOGEST Function in Excel: Exponential Curve Fit
LOGEST Function in Excel: Exponential Curve Fit
LOGEST fits y = b·mˣ and returns m (the growth factor) and b. m of 1.05 means 5% growth per period.
Read article →LINEST Function in Excel: Full Regression Statistics
LINEST Function in Excel: Full Regression Statistics
LINEST fits a straight line (or a multiple regression) and returns slope, intercept and, optionally, R², standard errors and more — an entire regression…
Read article →RANK Function in Excel: The Old Ranking Function
RANK Function in Excel: The Old Ranking Function
RANK still works for compatibility and behaves exactly like RANK.EQ. New workbooks should use RANK.EQ or RANK.AVG.
Read article →PERCENTRANK.EXC Function in Excel: Percentile Position, Excluding Ends
PERCENTRANK.EXC Function in Excel: Percentile Position, Excluding Ends
PERCENTRANK.EXC works like PERCENTRANK.INC, but never returns exactly 0 or 1 — matching the EXC family of percentile functions.
Read article →HARMEAN Function in Excel: The Right Average for Rates
HARMEAN Function in Excel: The Right Average for Rates
HARMEAN averages rates properly. Drive 60 km/h one way and 40 km/h back, and your average speed is 48, not 50.
Read article →Slow Wi-Fi at Home? 10 Fixes That Actually Work
Slow Wi-Fi at Home? 10 Fixes That Actually Work
Diagnose and fix slow home Wi-Fi: speed tests the right way, router placement, 2.4 GHz vs 5 GHz, channel congestion, DNS, restarting, firmware, mesh…
Read article →AVEDEV Function in Excel: Average Distance From the Mean
AVEDEV Function in Excel: Average Distance From the Mean
AVEDEV is the average of absolute deviations — an easier-to-explain measure of spread than standard deviation (“on average we are off by 12 units”).
Read article →DEVSQ Function in Excel: Sum of Squared Deviations
DEVSQ Function in Excel: Sum of Squared Deviations
DEVSQ adds up how far each value is from the mean, squared. It is the raw ingredient of variance and of ANOVA tables.
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