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
If the covariance is 1225, variance of x is 1600,variance of y is 2500 then the correlation coefficient between x and y is 0.6125.
Given the covariance is 1225, variance of x is 1600,variance of y is 2500.
We have to find the correlation coefficient between x and y.
Covariance is basically a measure of the joint variability of two random variables.
Variance is a basically a measure of dispersion, meaning it is a measure of how far a set of numbers is spread out from their average value.
The correlation coefficient is basically the specific measure that quantifies the strength of the linear relationship between two variables in a correlation analysis.
We know that the formula of correlation coefficient is as under:
r=
r=1225/
r=1225/(40*50)
r=1225/2000
r=0.6125
Hence if the covariance is 1225, variance of x is 1600,variance of y is 2500 then the correlation coefficient between x and y is 0.6125.
Learn more about correlation coefficient at brainly.com/question/4219149
#SPJ4
Answer:
Step-by-step explanation:
To find slope, use two points.
Point A
and Point B
.
Slope (m) =
.
Answer:
c. 34
Step-by-step explanation:
68% of 50 is 34
You multiply 50 and 68% (.68)
Answer:
simple 11
Step-by-step explanation: