# Find the mean and variance of this set of 40 numbers

• jinx007
In summary, the problem involves finding the mean and variance of a set of 40 numbers generated by a computer, consisting of 23 zeros and 17 twos. The mean can be calculated by adding all the numbers and dividing by the total number of numbers, while the variance can be found using the formula Variance(X)= Mean( (X - mean(X))^2 ). The mean is 0.850 and the variance is 0.978.
jinx007
A computer can generate random numbers which are either 0 or 2. On a particular occasion, it
generates a set of numbers which consists of 23 zeros and 17 twos. Find the mean and variance of this set of 40 numbers.

Please help i just don't know where to start. In fact i am thinking of using the formula mean = np but i cannot relate it to the question.

According to the booklet the answer for the mean is 0.850 and variance = 0.978

For the mean: just add up all the numbers (that is the 23 zeros and the 17 twos) and divide through the amount of numbers that you have added up.

For the variance: use the formula Variance(X)= Mean( (X - mean(X))^2 ), so for each number calculate (X- mean(X))^2, add these all up and divide though the amount of numbers you have added up

gerben said:
For the mean: just add up all the numbers (that is the 23 zeros and the 17 twos) and divide through the amount of numbers that you have added up.

For the variance: use the formula Variance(X)= Mean( (X - mean(X))^2 ), so for each number calculate (X- mean(X))^2, add these all up and divide though the amount of numbers you have added up

Oh if i understand you, you are saying that i must add 17 and 23 which is equal to 40 then i divide by 40.. ? but the answer is not correct, or i have misinterpreted you..??

If i know how to find the mean i can work out the variance. Just help me to find the mean.!

add up 17 twos and 23 zeros and divide by 40

## 1. What is the mean of a set of numbers?

The mean is the average value of a set of numbers. It is calculated by adding all the numbers in the set and dividing the sum by the total number of values in the set.

## 2. How is the mean calculated?

The mean is calculated by adding all the numbers in the set and then dividing the sum by the total number of values in the set. This is represented by the formula: mean = sum of all values / total number of values.

## 3. What is the importance of calculating the mean?

Calculating the mean allows us to determine the central tendency or average value of a set of numbers. It can help us understand the overall trend or pattern in the data and make comparisons between different sets of numbers.

## 4. What is the variance of a set of numbers?

The variance is a measure of how spread out or dispersed the data is in a set of numbers. It is calculated by finding the difference between each number and the mean, squaring the differences, and then finding the average of these squared differences.

## 5. How is the variance calculated?

The variance is calculated by finding the difference between each number and the mean, squaring the differences, and then finding the average of these squared differences. This is represented by the formula: variance = sum of (each value - mean)^2 / total number of values.

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