### 8.4 Expecting the Unexpected

<
>
• Math Help

You can use a spreadsheet to find the probabilities in Example 3. First, note that and that each factor is less than the previous factor.

1. Enter 1 into cell A1.
2. Enter the formula = A1 - 1/366 into cell A2.
3. Select cell A2. From the Edit menu, choose Copy.
4. Select cells A3 through A35. From the Edit menu, choose Paste.
5. Enter the formula = PRODUCT(A1:A35) into cell A36.
6. Enter the formula = 1 - A36 into cell A37.
• Consumer Suggestion

Girls, have you ever wanted to wear the same dress as your favorite actress? Websites like edressme.com sell celebrity knock-off dresses that are fashioned after dresses that popular celebrities wear to major events, such as the academy awards.

• Checkpoint Solution

The spreadsheet below shows the probability that all 40 students have different birthdays.

The probability that all 40 students have different birthdays is 10.95%. So, the probability that at least 2 students have the same birthday is

These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.

```  _  _      ___     _____      ______    _____
| \| ||   / _ \\  |  __ \\   /_   _//  / ____||
|  ' ||  / //\ \\ | |  \ ||   -| ||-  / //---`'
| .  || |  ___  ||| |__/ ||   _| ||_  \ \\___
|_|\_|| |_||  |_|||_____//   /_____//  \_____||
`-` -`  `-`   `-`  -----`    `-----`    `----`

```