SD - mean

The mean is 10 and the standard deviation is 3.5. If the data set contains 40 data values, approximately how many of the data values will fall within the range of 6.5 to 13.5?

Correct result:

x =  40

Solution:

$$\begin{gathered} n=40 \\ m=10 \\ s=3.5 \\ D=13.5-6.5=7 \\ q=D\mathrm{/}s=7\mathrm{/}3.5=2 \\ x=0.6826\cdot 40=27.304=40 \end{gathered}$$

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Showing 3 comments:

Ivo

Rule 1 sigma for a normal distribution (from the average on both sides distance standard deviation sigma) lies 68.26% of the values, if are normally distributed.

4 years ago  Like

Math student

please I don't get the last part of the solution

2 years ago  Like

Dr Math

please use our normal distribution calculator:

https://www.hackmath.net/en/calculator/normal-distribution?mean=10&sd=3.5&above=&below=&area=between&ll=6.5&ul=13.5&outsideLL=&outsideUL=&draw=Calculate

2 years ago  Like

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