# Calculate the standard deviance (statistics)

• RedonYellow
In summary, the conversation is about calculating the standard deviation in a statistics problem. The person is asking for help with their method of solving and mentions getting an answer of 4.40, but the example answer is 3.50. They are unsure of how to calculate it to get the given answer and discuss the possibility of dividing by either 19 or 20 as the sample size.
RedonYellow
(solved) Calculate the standard deviation (statistics)

## Homework Statement

From this table of values, I'm supposed to calculate the standard deviance

## Homework Equations

Up until this point, I've had no problem calculating the standard deviance with my calculator by going to STAT> CALC > 1 and entering the table.

## The Attempt at a Solution

This is was my method of solving it this time, and my answer was 4.40. However, the answer in the example says to "Assume that the standard deviance is 3.50." I don't understand the basis of making such an assumption. How can I calculate the standard deviance in a way that will result in 3.50 as my answer?

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RedonYellow said:
However, the answer in the example says to "Assume that the standard deviance is 3.50." I don't understand the basis of making such an assumption.

If the question is saying to assume the population standard deviation is 3.5, this does not contradict getting a different answer for the sample standard deviation, which is what you calculated.

The only wiggle room that I see for you in calculating the sample standard deviation is whether you divide by 19 (the samle size minus 1) or 20 (the sample size). I haven't checked the arithmetic you did.

Never mind. I figured it out

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## What is standard deviation?

Standard deviation is a measure of how spread out a set of data is from its mean or average. It tells you how much variation there is in the data set.

## How do you calculate standard deviation?

To calculate standard deviation, you first need to find the mean of the data set. Then, for each data point, subtract the mean and square the result. Next, find the mean of these squared differences and take the square root of that value. This is the standard deviation.

## What is the purpose of calculating standard deviation?

The purpose of calculating standard deviation is to understand the spread or variability of a set of data. It can help identify outliers and determine the accuracy of the mean as a representation of the data set.

## What is the difference between population and sample standard deviation?

Population standard deviation is used when the entire population of data is available, while sample standard deviation is used when only a portion of the population is available. The calculation for sample standard deviation involves dividing by one less than the sample size, while population standard deviation involves dividing by the entire population size.

## Can standard deviation be negative?

No, standard deviation cannot be negative. It is always a positive value because the squared differences from the mean are always positive and the square root of a positive number is always positive.

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