The standard deviation of what? Percentiles from any normal distribution look the same, just like the unit normal, so you can't really determine the standard deviation of the original scores. You can determine a z score from a percentile. That tells us the number of standard deviations, positive or negative, a given score is away from the mean score. It's a normalized test result.
Your percentile is (a hundred times) the probability that another score is less than your score. We have a normal distribution, so that probability is the integral of the standard normal from negative infinity to our normalized score.
Let's call the percentile rank

, already scaled between zero and 1.

corresponds to a z score

because the fiftieth percentile means we got an exactly average score, 0 standard deviations away from the mean.
We know 68% of the probability will be between -1 and +1 standard deviation. So

corresponds to

and

corresponds to

Similarly, 95% of the probability will be between -2 and +2 standard deviations. So

corresponds to

and

corresponds to

That's about the list I can do off the top of my head. I think three standard deviations is 99.7%. For the rest we just consult a z table or integrated normal table. We find p in the body of the table (maybe |.5-p| depending on the table) and then the column headings tell us our z score.
In this modern age, your computer can do this for you quickly
<span>6a+14=-7-a
you simplify the equation to the form, which is simple to understand
<span>6a+14=-7-a
you move all terms containing a to the left and all other terms to the right.
<span>+6a+1a=-7-14
you need to simplify left and right side of the equation.
<span>+7a=-21
you divide both sides of the equation by 7 to get a.
<span>a=-3</span></span></span></span></span>
834/6=139
Each building will get 139 planks
Use long division
Answer:
x=25
Step-by-step explanation:
4x-10x=x-175
Move all the x values to one side:
175=x+10x-4x
Simplify:
175=7x
Divide both sides by 7:
25=x
The answer is y= -1
When the slope is 0, we refer to the line as a constant function. In slope intercept form, the line is equal to y = mx + b
"m" is the slope, and "b" is the y-intercept.
Let's replace those in the function.
y = 0*x - 1
0 multiplied by anything is 0
y = 0 - 1
y = -1