18 students are 100%-37,5%-40%=22,5%
So we know that 18 students equal to 22.5. And we are looking for the anwser what 100% of students is.
SO:
x students - 100%
(22 + 1/2)x =18×100
(22 + 1/2) can be represented as just 25.5
-//- = 1800
we need to divide bot sides by 25.5
x = 1800 / 25.5
... x = 80
90% confidence, it can be said that the population proportion of adults who believe in UFOs is between the endpoints of the giver confidence interval [ 0.3026, 0.3348 ].
Here, we have given:
Number of adults (n) = 2272
Number of adults who believe in UFO (x) = 724
Sample proportion (p) = x/n
p = 724 / 2272
p = 0.3187
now, let q = 1 - p
q = 1 - 0.3187
q = 0.6813
Confidence level → 90%
The 90% confidence interval for population proportion is
![[ p - 1.645\frac{\sqrt{pq} }{\sqrt{n}} ,p + 1.645\frac{\sqrt{pq} }{\sqrt{n}} ]](https://tex.z-dn.net/?f=%5B%20p%20-%201.645%5Cfrac%7B%5Csqrt%7Bpq%7D%20%7D%7B%5Csqrt%7Bn%7D%7D%20%2Cp%20%2B%201.645%5Cfrac%7B%5Csqrt%7Bpq%7D%20%7D%7B%5Csqrt%7Bn%7D%7D%20%5D)
where 1.645 is Zac value at 90% confidence level.
= 0.3187 - 0.0161 = 0.3026
= 0.3187 + 0.0161 = 0.3348
90% confidence interval for the population proportion is
[ 0.3026, 0.3348 ]
Hence, With 90% confidence, it can be said that the population proportion of adults who believe in UFOs is between the endpoints of the giver confidence interval [ 0.3026, 0.3348 ]
Learn more about " Population Proportion " from here: brainly.com/question/15087042
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45 + 30 = 15(3 + 2) = 15(5) = 75
Answer:
Step-by-step explanation:
Confidence interval for the difference in the two proportions is written as
Difference in sample proportions ± margin of error
Sample proportion, p= x/n
Where x = number of success
n = number of samples
For the men,
x = 318
n1 = 520
p1 = 318/520 = 0.61
For the women
x = 379
n2 = 460
p2 = 379/460 = 0.82
Margin of error = z√[p1(1 - p1)/n1 + p2(1 - p2)/n2]
To determine the z score, we subtract the confidence level from 100% to get α
α = 1 - 0.95 = 0.05
α/2 = 0.05/2 = 0.025
This is the area in each tail. Since we want the area in the middle, it becomes
1 - 0.025 = 0.975
The z score corresponding to the area on the z table is 1.96. Thus, confidence level of 95% is 1.96
Margin of error = 1.96 × √[0.61(1 - 0.61)/520 + 0.82(1 - 0.82)/460]
= 1.96 × √0.0004575 + 0.00032086957)
= 0.055
Confidence interval = 0.61 - 0.82 ± 0.055
= - 0.21 ± 0.055
