Answer:
a)
b)
c)
d)
Explanation:
From the question we are told that:
Population percentage 
Sample size 
Let x =customers ask for water
Let y =customers dose not ask for water with their meal
Generally the equation for y is mathematically given by

Generally the equation for pmf p(x) is mathematically given by

a)
Generally the probability that exactly 6 ask for water is mathematically given by


b)
Generally the probability that less than 9 ask for water with meal is mathematically given by




c)
Generally the probability that at least 3 ask for water with meal is mathematically given by

![p(x\geq3)=1-[p(0)+p(1)+p(2)]](https://tex.z-dn.net/?f=p%28x%5Cgeq3%29%3D1-%5Bp%280%29%2Bp%281%29%2Bp%282%29%5D)
![p(x\geq3)=1-[0.00001+0.0015+0.0106]](https://tex.z-dn.net/?f=p%28x%5Cgeq3%29%3D1-%5B0.00001%2B0.0015%2B0.0106%5D)
![p(x\geq3)=1-[0.0122]](https://tex.z-dn.net/?f=p%28x%5Cgeq3%29%3D1-%5B0.0122%5D)

d)
Generally the mean and standard deviation of sample size is mathematically given by
Mean

Standard deviation


"When we do experiments it's a good idea to do multiple trials, that is, do the same experiment lots of times. When we do multiple trials of the same experiment, we can make sure that our results are consistent and not altered by random events. Multiple trials can be done at one time."
Answer:
a) The minimum thickness of the oil slick at the spot is 313 nm
b) the minimum thickness be now will be 125 nm
Explanation:
Given the data in the question;
a) The index of refraction of the oil is 1.20. What is the minimum thickness of the oil slick at that spot?
t
= λ/2n
given that; wavelength λ = 750 nm and index of refraction of the oil n = 1.20
we substitute
t
= 750 / 2(1.20)
t
= 750 / 2.4
t
= 312.5 ≈ 313 nm
Therefore, The minimum thickness of the oil slick at the spot is 313 nm
b)
Suppose the oil had an index of refraction of 1.50. What would the minimum thickness be now?
minimum thickness of the oil slick at the spot will be;
t
= λ/4n
given that; wavelength λ = 750 nm and index of refraction of the oil n = 1.50
we substitute
t
= 750 / 4(1.50)
t
= 750 / 6
t
= 125 nm
Therefore, the minimum thickness be now will be 125 nm