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
Answer:
k;p
Step-by-step explanation:
If they are parallel they will have the same slope , m
So in y = mx + c, if there are two equations which both have the same m value they will be parallel.
If the lines are perpendicular they'll have slopes like this: 1/2 to -2/1 - where they flip and a negative gets added.
In the equations: 10x + 5y = -5 , and y = -2x + 6
We can rearrange 10x + 5y = -5 to be in the form y = mx + c
10x + 5y = -5
5y = -5 - 10x
y = -1 - 2x
y = -2x - 1
Since y = -2x - 1 and y = -2x + 6 both have the same slope of -2 they are parallel!
Answer:
405
Step-by-step explanation:
So he built 5/9 of the wall, than added the extra 180 bricks to finish the wall.
so 5/9 + 180 = 9/9
so 180 = 4/9 Because 5/9 + 4/9 = 9/9
So to figure out how many bricks are in the wall we want to know what 1/9 of bricks equals and to work this out we need to divide 180 by 4
which equals 45.
Now we know that 1/9 = 45
so now to figure out what 9/9 is just multiply 45 by 9 which equals 405
Answer:
It is unlikely that they will be the same rank 2/52 chance witch is a 0.03% chance
Step-by-step explanation: