# Statistics. Determining the mean.

• Feb 17th 2013, 02:25 AM
Lisa1992
Statistics. Determining the mean.
Hello! Can someone help me please with this exercise?

The Kentucky Derby is held the first Saturday in May at Churchill Downs in Louisville, Kentucky. The race track is one and one-quarter miles. The following table shows the winners since 1990, their margin of victory, the winning time, and the payoff on a \$2 bet.

Determine the mean for the payoff on a \$2 bet. (Round your Mean answers to 4 decimal places )

My answer for the mean of the payoff on a \$2 bet is 29.8040, but it's not right!http://www.talkstats.com/images/smilies/shakehead.gifAttachment 27079
• Feb 17th 2013, 04:33 AM
HallsofIvy
Re: Statistics. Determining the mean.
It seems very strange that you would be asked to find the mean if you had never been given the definition of "mean"! Add all the numbers in the list under "\$2 bet" and divide by the number of entries in the list.
• Feb 17th 2013, 05:37 AM
ILikeSerena
Re: Statistics. Determining the mean.
Hi Lisa1992! :)

It looks like you made a typo.
Your result is close but it should be something like 25.0333.
• Feb 17th 2013, 08:03 AM
Lisa1992
Re: Statistics. Determining the mean.
Well, thank you! but i wanted to use frequency distribution, so i used 5 classes with the intervall of 23 and got this result. Still it should give the same result as i thought...it becomes easer to find out std.deviation afterwards...
• Feb 17th 2013, 08:09 AM
ILikeSerena
Re: Statistics. Determining the mean.
I get:

Code:

```Payoff        6.3        9.6        7.8        10.6        43.5        5.5        5.2        4.9        7.6        30.2         53.3        11.7        8.8        4.1        8.4        9.7        101.5        118.9        24.8        20.7        32.6 Sum        525.7                                                                                                                                                        Count        21                                                                                                                                                        Mean        25.03333333```
What kind of sum did you get?
• Feb 17th 2013, 08:13 AM
Lisa1992
Re: Statistics. Determining the mean.
thank you! i used calculater and got the same. but i changed my previous post ... so it can be done without frequency distribution, since it gives not exact answer...
• Feb 17th 2013, 08:17 AM
ILikeSerena
Re: Statistics. Determining the mean.
Quote:

Originally Posted by Lisa1992
thank you! i used calculater and got the same. but i changed my previous post ... so it can be done without frequency distribution, since it gives not exact answer...

Sure! ;)

I'm afraid that indeed with a frequency distribution you can't get the mean or standard deviation any more.
You need the original number to get those properly.
• Feb 17th 2013, 08:22 AM
Lisa1992
Re: Statistics. Determining the mean.
All right! I got it :)