# Probability UNITS? (1 Viewer)

### Users Who Are Viewing This Thread (Users: 0, Guests: 1)

#### meee

hihi
for example, im doing a question involving the probability of the number of apples i eat in a day.

i need to find the mean, mode, median, variance and standard deviation.

do these values need to be in units of apples? or just like a numerical value such as 2.3 ?

thanks

#### Manchot

In the standard way of definining it, probability values are unitless. Say you had 2 green apples and 1 red apple. The probability of you picking a red apple is (1 apple)/(3 apples)=1/3. Essentially, the units of "apple" cancel, leaving only a number.

However, the mean, mode, median, variance, and standard deviation all have units. The first three are essentially ways of averaging, and so must have units of apples. The variance has units of apples^2, and the standard deviation has units of apples.

#### meee

wow i never wuda thought maybe the other things but not variance being apple squared thanks

### The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving