Standard deviation, Normal Distributions and Taking Random Samples

In summary, the standard score for the data value 9 from a normal distribution with a mean of 16.8 and a standard deviation of 2.3 can be found using the formula z = (9 - 16.8) / 2.3.
  • #1
DarcyDorian
1
0
Find the standard score for a the data value 9 from a normal distribution which has a
mean of 16.8 and a standard deviation of 2.3
 
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  • #2
Hello and welcome to MHB, DarcyDorian! :D

We ask that our users show their progress (work thus far or thoughts on how to begin) when posting questions. This way our helpers can see where you are stuck or may be going astray and will be able to post the best help possible without potentially making a suggestion which you have already tried, which would waste your time and that of the helper.

Assuming you don't know how to begin, we will need the following formula:

[box=green]
The Normal Distribution

$z$-score for an $x$-value: \(\displaystyle z=\frac{x-\mu}{\sigma}\)[/box]

Now, we are given $x=9$, $\mu=16.8$ and $\sigma=2.3$, so can you use the above formula to compute $z$ (the standard score)? :)
 

Related to Standard deviation, Normal Distributions and Taking Random Samples

1. What is standard deviation and why is it important?

Standard deviation is a measure of how spread out data is from the mean. It is important because it helps us understand the variability of a data set and can be used to compare different data sets.

2. What is a normal distribution and why is it useful?

A normal distribution is a bell-shaped curve that represents the probability distribution of a data set. It is useful because many natural phenomena follow this pattern, making it a useful tool for analyzing and predicting data.

3. What is the difference between a population and a sample?

A population is the entire group of individuals or objects being studied, while a sample is a subset of that population. Samples are often used in research as they are more manageable to study and can provide information about the larger population.

4. How do you calculate standard deviation?

To calculate standard deviation, you first find the mean of the data set. Then, for each data point, subtract the mean and square the result. Next, find the sum of all the squared differences and divide by the total number of data points. Finally, take the square root of this result to find the standard deviation.

5. Why is it important to take random samples?

Taking random samples helps to ensure that the data collected is representative of the entire population. This reduces the risk of bias and allows for more accurate conclusions to be drawn from the data.

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