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
The amount gotten after $1689 invested for 4 years at 3% compounded annually is $1901
The amount of money gained after an investment is compounded is given by:

Where P is principal, A is the final amount, r is the rate, n is the number of times compounded per period and t is the time
Given that P = $1689, t = 4, r = 3% = 0.03, n = 1, hence:

The amount gotten after $1689 invested for 4 years at 3% compounded annually is $1901
Find out more at: brainly.com/question/14295570
Answer:
16
Step-by-step explanation:
b^2
Let b= -4
(-4)^2
16
Answer:
Final answer is 1/3.
Step-by-step explanation:
Question says that Mrs Jenkins picked some tomatoes from her garden. She used 5/9 of the tomatoes to make pasta sauce. After that she used 3/4 of the remainder to make a salad. Now we need to find about what fraction of the tomatoes did Mrs Jenkins use to make the salad.
As she used 5/9 of the tomatoes to make pasta sauce.
Now remaining amount of tomatoes = 1- 5/9 = 9/9 -5/9 = 4/9
Then she used 3/4 of the remainder to make a salad. So fraction of the tomatoes did Mrs Jenkins use to make the salad = (4/9)(3/4)=12/36=1/3
Hence final answer is 1/3.
Answer:
b = -57/10
Step-by-step explanation:
Let's first distribute everything out:
-8(1 + 5b) = -8 * 1 + (-8) * 5b = -8 - 40b
2(86 - 1) = 2 * 85 = 170
So, we have:
-8 - 40b - 170 = 50
-40b - 178 = 50
-40b = 50 + 178 = 228
b = -228/40 = -57/10
Thus, the answer is b = -57/10.
Hope this helps!