courses › Business Stats & Decisions

Mean, median, weighted averages, and how spread out results are.

In your head, jot if needed · no calculator why?

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Opens at level 12.

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skills · practice stats

From rounds of this course only: box, review and trial answers are left out. Once a skill has 40 tries, it compares your first 20 tries with your last 20.

• Median par 14 s not tried yet

  worked example

  Four job values are $150, $250, $270, and $1,170. What is the median job value?

  Answer: $260.00

  1. Sort them: $150, $250, $270, $1,170.
  2. With an even count, average the middle two: ($250 + $270) ÷ 2 = $260.

• Mean par 14 s not tried yet

  worked example

  Five job values are $60, $70, $220, $260, and $390. What is the mean job value?

  Answer: $200.00

  1. Total $1,000 ÷ 5 jobs = $200.

• Weighted average par 18 s not tried yet

  worked example

  Eight jobs average $460 and seven jobs average $130. What is the average across all fifteen jobs?

  Answer: $306.00

  1. Totals first: 8 × $460 = $3,680 and 7 × $130 = $910.
  2. $3,680 + $910 = $4,590; ÷ 15 jobs = $306.

• Standard deviation of three values par 20 s not tried yet

  worked example

  Three jobs took 21, 35, and 49 hours. What is the sample standard deviation, in hours, dividing by n − 1?

  Answer: 14 hours

  1. Mean 35. Squared gaps from the mean: 196 + 0 + 196 = 392.
  2. Divide by n − 1 = 2: 196. Square root: 14 hours.

rest ladder

Win 3 of your last 4 rounds and the course rests. A win is 90% right, within 2× the round's par. Pass the review when it comes back and the next rest is longer.

1. 1 day
2. 3 days
3. 7 days
4. 14 days
5. 30 days
6. 60 days
7. mastered · every 90 days

your rounds

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