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
About 400 zebras live at the game reserve.
The proportion would be
30/150 = 80/x
This is because 30 zebras are tagged out of 150 in one area. We know that they tagged 80 total zebras out of x total zebras.
To solve this, cross multiply:
x*30 = 150*80
30x = 12000
Divide both sides by 30:
30x/30 = 12000/30
x = 400
Answer:
option d is correct
Step-by-step explanation:
hope this helped
Answer:
o calculate the volume of a cone, start by finding the cone's radius, which is equal to half of its diameter. Next, plug the radius into the formula A = πr^2, where A is the area and r is the radius. Once you have the area, multiply it by the height of the cone.Step-by-step explanation:
their you go your answer plz rate me the most brainlest