Answer:
a) All of them are out of charge = 9.31x10⁻¹⁰
b) 20% of them are out of charge = 5.529x10⁻⁴
Step-by-step explanation:
This problem can be modeled as a binomial distribution since
There are n repeated trials and all of them are independent of each other.
There are only two possibilities: battery is out of charge and battery is not out of charge.
The probability of success does not change with trial to trial.
Since it is given that it is equally likely for the battery to be out of charge or not out of charge so probability of success is 50% or 0.50
P = 0.50
1 - P = 0.50
a) All of them are out of charge?
Probability = nCx * P^x * (1 - P)^n-x
Probability = ₃₀C₃₀(0.50)³⁰(0.50)⁰
Probability = 9.31x10⁻¹⁰
b) 20% of them are out of charge?
0.20*30 = 6 batteries are out of charge
Probability =₃₀C₆(0.50)²⁴(0.50)⁶
Probability = 5.529x10⁻⁴
Answer:
The sample size to obtain the desired margin of error is 160.
Step-by-step explanation:
The Margin of Error is given as
Rearranging this equation in terms of n gives
![n=\left[z_{crit}\times \dfrac{\sigma}{M}\right]^2](https://tex.z-dn.net/?f=n%3D%5Cleft%5Bz_%7Bcrit%7D%5Ctimes%20%5Cdfrac%7B%5Csigma%7D%7BM%7D%5Cright%5D%5E2)
Now the Margin of Error is reduced by 2 so the new M_2 is given as M/2 so the value of n_2 is calculated as
![n_2=\left[z_{crit}\times \dfrac{\sigma}{M_2}\right]^2\\n_2=\left[z_{crit}\times \dfrac{\sigma}{M/2}\right]^2\\n_2=\left[z_{crit}\times \dfrac{2\sigma}{M}\right]^2\\n_2=2^2\left[z_{crit}\times \dfrac{\sigma}{M}\right]^2\\n_2=4\left[z_{crit}\times \dfrac{\sigma}{M}\right]^2\\n_2=4n](https://tex.z-dn.net/?f=n_2%3D%5Cleft%5Bz_%7Bcrit%7D%5Ctimes%20%5Cdfrac%7B%5Csigma%7D%7BM_2%7D%5Cright%5D%5E2%5C%5Cn_2%3D%5Cleft%5Bz_%7Bcrit%7D%5Ctimes%20%5Cdfrac%7B%5Csigma%7D%7BM%2F2%7D%5Cright%5D%5E2%5C%5Cn_2%3D%5Cleft%5Bz_%7Bcrit%7D%5Ctimes%20%5Cdfrac%7B2%5Csigma%7D%7BM%7D%5Cright%5D%5E2%5C%5Cn_2%3D2%5E2%5Cleft%5Bz_%7Bcrit%7D%5Ctimes%20%5Cdfrac%7B%5Csigma%7D%7BM%7D%5Cright%5D%5E2%5C%5Cn_2%3D4%5Cleft%5Bz_%7Bcrit%7D%5Ctimes%20%5Cdfrac%7B%5Csigma%7D%7BM%7D%5Cright%5D%5E2%5C%5Cn_2%3D4n)
As n is given as 40 so the new sample size is given as
So the sample size to obtain the desired margin of error is 160.
To find the total amount Leo should give, simply find the 20% of his bill then add it.
Total cost = $45.90 + ($45.90 × 0.20)
Total cost = $45.90 + $9.18
Total cost = $55.08
Therefore, Leo should give $55.08 in total to leave a 20% tip.
Alright.
So let's say the number of adults is x.
Therefore, the number of boys is 7x + 1.
And then the total amount of girls is 3.5x + 0.5
So then:
x + 7x + 1 + 3.5x + 0.5 = 82
11.5x + 1.5 = 82
11.5x = 80.5
x = 7
So now we can figure out the number of male and female students.
Male students = 7x + 1
7*7 + 1
49 + 1
50
Male Students = 50
Female students = half of 50
50/2 = 25
Female Students = 25
