Respuesta :
Answer: 0.0869
Step-by-step explanation:
Given data:
No of college women = 209
Probability that 72% had been on a diet
Solution:
Standard deviation = √ p ( 1-p)/n
= √ 0.69 ( 1-0.69) / 209
= 0.02213
Z = x - u / standard deviation
= 0.72 - 0.69 / 0.02213
= 1.36
P( p ≥ 72 ) =( z< -13.56 )
= 0.0869
The probability that 72% of the women has been exercising for 12 month is 0.0869.
Using the Normal Distribution and the Central Limit Theorem, it is found that there is a 0.1736 = 17.36% probability that 72% or more of the women in the sample have been on a diet.
In a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
- It measures how many standard deviations the measure is from the mean.
- After finding the z-score, we look at the z-score table and find the p-value associated with this z-score, which is the percentile of X.
- By the Central Limit Theorem, for sampling distribution of the sample proportion of size n, with an estimate of p, the mean is [tex]\mu = p[/tex] and the standard error is [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex].
In this problem, [tex]p = 0.69, n = 209[/tex], hence, the mean and the standard error are given by:
[tex]\mu = p = 0.69[/tex]
[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.69(0.31)}{209}} = 0.032[/tex]
The probability that 72% or more of the women in the sample have been on a diet is 1 subtracted by the p-value of Z when X = 0.72, hence:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.72 - 0.69}{0.032}[/tex]
[tex]Z = 0.94[/tex]
[tex]Z = 0.94[/tex] has a p-value of 0.8264.
1 - 0.8264 = 0.1736.
0.1736 = 17.36% probability that 72% or more of the women in the sample have been on a diet.
A similar problem is given at https://brainly.com/question/15413688