Answer:
20000*(1+15%)³=30417.5
Explanation:
The number $40000 is irrelevant. Don't be disturbed!
This is a typical compound interest question. Use the compound interest formula: S=p(1+<em>i)ⁿ</em>
S for sum, p for principal balance, <em>i </em>for interest rate, n for the number of years or times
Let Z be a random variable following the standard normal distribution with mean µ = 0 and standard deviation σ = 1.
The 67th percentile of the distribution is the value z that separates the bottom 67% of the distribution from the top 100% - 67% = 33%. In terms of probability, we have
Pr[Z ≤ z] = 0.67
Use the inverse CDF for the normal distribution (or lookup z scores in a table) to find
z = ɸ⁻¹(0.67) ≈ 0.4399
where ɸ(z) is the CDF for the normal distribution.
95.44% IQ scores are between 77 and 125
We're given,
Mean (a)=101
standard deviation (b)=12
To find : ![P[77 < x < 125]](https://tex.z-dn.net/?f=P%5B77%20%3C%20x%20%3C%20125%5D)
Using Empirical Rule:
∴
![P[\frac{77-101}{12} < \frac{x-a}{b} < \frac{125-101}{12}]\\](https://tex.z-dn.net/?f=P%5B%5Cfrac%7B77-101%7D%7B12%7D%20%3C%20%5Cfrac%7Bx-a%7D%7Bb%7D%20%3C%20%5Cfrac%7B125-101%7D%7B12%7D%5D%5C%5C)
![=P[-2 < z < 2]\\](https://tex.z-dn.net/?f=%3DP%5B-2%20%3C%20z%20%3C%202%5D%5C%5C)
![=P[Z < 2]-P[Z < -2]\\](https://tex.z-dn.net/?f=%3DP%5BZ%20%3C%202%5D-P%5BZ%20%3C%20-2%5D%5C%5C)

=95.44% (approx)
Learn more about Empirical rule of IQ calculation here:
brainly.com/question/13077017
#SPJ10
The scientists ensure that their results are reliable by repeating trials.
Given that scientists ensure that their results are reliable.
We are required to tell the way how scientists ensure that their results are reliable.
Reliability is basically defined as the probability that a product, system, or service will perform its intended function adequately for a specified period of time, or will operate in a defined environment without failure.
Reliability increases from repeating trials.It is like vaccines. Firstly the trials to be made on small number of persons, then the numbers increases and then ultimately the trials are done on the large number of persons.
Hence the scientists ensure that their results are reliable by repeating trials.
Learn more about reliability at brainly.com/question/1265793
#SPJ4