# How Do I Work Standard Deviation Problems

*The solution is to take a sample of the population, say 1000 people, and use that sample size to estimate the actual weights of the whole population. Important note: The standard deviation formula is slightly different for populations and samples (a portion of the population ). Step 2: Subtract the mean and square the result. Sample question: Find the sample variance in Excel for the following sample data: 123, 129, 233, 302, 442, 542, 545, 600, 694, 777 Step 1: Type your data into a single column in an Excel worksheet. Square that for a total of nine. *

### Mean and Standard deviation - Problems with Solutions

## Standard Deviation Problems - Matemticas - vitutor Standard Deviation and Variance - Math is Fun

Find out more about page archiving. Problem #3: The standard deviation of a student's grades is zero. So now take the area from a z-score of 0.7879 (same thing as before). This page has been archived and is no longer updated. Now you are ready for a couple of standard deviation problems. Solution: 100 is 2 standard deviations below the mean ( ) 140 is 2 standard deviations above the mean ( ) 95 of people have a score between 100 and 140. If a set of data has a distribution that is bell shape, then the following properties apply: About 68 of all the values fall within 1 standard deviation of the mean.

The key to solving this problem is to see that 61 and 79 inches are each exactly 3 standard deviations from the mean 3 s and.

Before we practice with some standard deviation problems, let us see how we can interpret the standard deviation.

With relation to the normal curve, this would be the area from -infty to your z-score.

Mathematically, we can write: mean - s x mean.

What do you know about the grades of this student?

Problem #1: Suppose the heights of men in a country have a bell-shaped distribution with a mean of 70 inches and a standard deviation of 3 inches. The student's grade is unpredictable. The score of 90 will be considered low and somewhat average while the score of 160 is considered to be gifted.

Here are the amounts of gold coins the 5 pirates have.

This turns out to be approx.4616. Show answer, new math lessons, your email is safe with. B) The z-score in the middle is zero. Therefore,.7 of men have a height between 61 inches and 79 inches.