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# Calculating the mean of a discrete data set Watch

1. The question asks for me to find the mean per month of cars bought over a duration of 10 months. I get a decimal answer but since we are dealing with a discrete set of data, do I round up?

Also, when I calculate the median, do I also round up if I get a decimal number after calculating a discrete set?

Many thanks!
2. I know it's weird, but you don't need to return a whole number of cars when reporting a mean.
(In fact, in instances such as logistic regression, where you have a sequence of 0's and 1's, just reporting either 0 or 1 would stump the whole process).

The median will always be either an integer or an integer + 1/2.
3. (Original post by placenta medicae talpae)
I know it's weird, but you don't need to return a whole number of cars when reporting a mean.
(In fact, in instances such as logistic regression, where you have a sequence of 0's and 1's, just reporting either 0 or 1 would stump the whole process).

The median will always be either an integer or an integer + 1/2.
Thanks for the response! But we'll be using a continuous variable for the mean though...

Looking back at my notes, I agree with your response on the median.
4. (Original post by captainchalk)
The question asks for me to find the mean per month of cars bought over a duration of 10 months. I get a decimal answer but since we are dealing with a discrete set of data, do I round up?

Also, when I calculate the median, do I also round up if I get a decimal number after calculating a discrete set?

Many thanks!
If, over a number of time periods, the mean was 3.41, 3.25, 3.08, 2.94, 2.73, 2.60 and it was your job to report it, would you be happy telling your boss that the mean has been 3 for the last 6 periods?
5. (Original post by BabyMaths)
If, over a number of time periods, the mean was 3.41, 3.25, 3.08, 2.94, 2.73, 2.60 and it was your job to report it, would you be happy telling your boss that the mean has been 3 for the last 6 periods?
I don't understand how your argument is relevant.
6. (Original post by captainchalk)
Thanks for the response! But we'll be using a continuous variable for the mean though...
Yep.

Have you done any stats?
If not, ignore this spoiler:

Spoiler:
Show
Bernoulli random variables take the values 0 or 1, and nothing else. The mean of the Bernoulli distribution is p though, which could be 0.5 or 0.3 or whatever.
Similarly, the mean of the binomial distribution, np could be say 24.4, but realisations of the binomial random variable will always be integers. If you said that the mean of the random variable were 24, then you would be describing a different distribution.
7. (Original post by placenta medicae talpae)
Yep.

Have you done any stats?
If not, ignore this spoiler:

Spoiler:
Show
Bernoulli random variables take the values 0 or 1, and nothing else. The mean of the Bernoulli distribution is p though, which could be 0.5 or 0.3 or whatever.
Similarly, the mean of the binomial distribution, np could be say 24.4, but realisations of the binomial random variable will always be integers. If you said that the mean of the random variable were 24, then you would be describing a different distribution.
Ohhh! Thank you!

And yes, I have read up on Bernoulli before.
8. (Original post by captainchalk)
I don't understand how your argument is relevant.
It's not an argument, it's an example. Rounding to a whole number could conceal a trend. It is relevant to your original question.

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