Most of your days can beat your "average day." That sounds impossible, until one breakdown drags the average down for everyone.
Learning objectives. After this week you can (1) compute the mean, median, mode and range of your daily nets; (2) explain why one bad day moves the mean but barely moves the median; and (3) read a trend and make a simple forecast.
Remember this: one wild day drags the mean. The median barely moves.
1) Your season is a dataset
Every close adds one row to your season history, and its Net column is your daily net. By now you have dozens of rows. Statistics turns "how did we do?" from a feeling into a number.
2) The three middles
Mean = Sum of values ÷ Count ·
Median = middle value when sorted ·
Mode = most frequent value
Range = Highest − Lowest
A week of daily nets with one breakdown day: $180, $220, −$140, $260, $240, $310, $330.
- Mean: the sum is $1,400, so 1,400 ÷ 7 = $200.
- Median: sorted, −140, 180, 220, 240, 260, 310, 330. The middle value is $240.
- Range: 330 − (−140) = $470.
Even count? Average the middle two. For $120, $180, $240, $260 the median is (180 + 240) ÷ 2 = $210, and the mean is 800 ÷ 4 = $200.
Try it
Your last 5 closes brought in $2,840 between them.
Mean = Total ÷ Number of days
Fill in the boxes.
3) When the average lies
In the week above, five of seven days beat the $200 mean. The one −$140 day pulled the mean $40 below the median. That is the pattern: an extreme day, good or bad, drags the mean a long way and barely moves the median. Breakdowns and rare huge event days are outliers like that. If you bought a truck, that day's Net carries the $10,000 price, and it is the biggest outlier of all. It still counts. Report the mean and the median, and when they disagree, the gap tells you how lopsided your season has been.
Try it
Now a breakdown day costs you $400. Add it to that $2,840 and take the mean over 6 days.
New mean = (Total + Bad day) ÷ Days
Fill in the boxes.
4) Spread and trend
Team A nets $200, $210, $190, $205, $195. Team B nets $500, −$100, $450, −$50, $200. Both have a mean of $200, but A's range is $20 and B's is $600. Same mean, far more risk.
A trend compares a recent stretch with an earlier one. In the week above, the first three days average (180 + 220 − 140) ÷ 3 ≈ $87 and the last three (240 + 310 + 330) ÷ 3 ≈ $293: improving. A fair forecast for the next close is the average of your last few comparable days, not the season mean.
Quick self-check
Five closes: $140, $260, $200, $180, $220. (a) Mean? (b) Median? (c) Range? (d) What is the mode of $200, $200, $300, $400? (Answers: 1,000 ÷ 5 = $200; sorted middle = $200; 260 − 140 = $120; $200.)
Common mistakes
- Forgetting to sort. The median is the middle of the sorted list.
- Picking one middle value on an even count. Average the middle two.
- Mixing different kinds of days. Group similar days first, then average them to forecast.
This week in the arena
Copy the Net column from your season history. Compute the mean and the median, and say which is higher. Then circle your best and worst days. Are they pulling your mean up or down? Make one forecast for your next close and check it the morning after.