The biologist is studying Black Carp invasiveness in Lake Ontario next. He doesn't have time to sample the fish himself, so instead he instead asks a fisherman who has been fishing off of one of Toronto's piers all morning about his catch. The fisherman responds that, of the 75 fish he has caught, 47 have been Black Carp. What is the lower bound of a 99% confidence interval for the true proportion of fish that are Black Carp in Lake Ontario

Respuesta :

Answer:

The 99% confidence interval for the true proportion of fish that are Black carp in Lake Ontario

(0.4828 , 0.7704)

Step-by-step explanation:

Step(i):-

Given that the fisherman responds that, of the 75 fish he has caught, 47 have been Black carp

Sample proportion = [tex]\frac{x}{n} = \frac{47}{75} = 0.6266[/tex]

We have to find the 99% confidence interval for the true proportion of fish that are Black carp in Lake Ontario

Step(ii):-

solution:-

Given that the level of significance = 0.01

Z-score = 2.576

The 99% confidence interval for the true proportion of fish that are Black carp in Lake Ontario

[tex](p^{-} - Z_{0.01} \sqrt{\frac{p(1-p)}{n} } , p^{-} +Z_{0.01} \sqrt{\frac{p(1-p)}{n} })[/tex]

[tex](0.6266 - 2.576 \sqrt{\frac{0.6266(1-0.6266)}{75} } ,0.6266 +2.576 \sqrt{\frac{0.6266(1-0.6266)}{75} })[/tex]

After calculation, we get

(0.6266 - 0.1438 , 0.6266 +0.1438)

(0.4828 , 0.7704)

Final answer:-

The 99% confidence interval for the true proportion of fish that are Black carp in Lake Ontario

(0.4828 , 0.7704)

Using the z-distribution, it is found that the lower bound of a 99% confidence interval for the true proportion of fish that are Black Carp in Lake Ontario is 0.4829.

What is a confidence interval of proportions?

A confidence interval of proportions is given by:

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which:

  • [tex]\pi[/tex] is the sample proportion.
  • z is the critical value.
  • n is the sample size.

In this problem, for the parameters, we have that:

  • 99% confidence level, hence[tex]\alpha = 0.99[/tex], z is the value of Z that has a p-value of [tex]\frac{1+0.99}{2} = 0.995[/tex], so [tex]z = 2.575[/tex].
  • Of the 75 fish he has caught, 47 have been Black Carp, hence [tex]n = 75, \pi = \frac{47}{75} = 0.6267[/tex]

The lower bound of the interval is:

[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.6267 - 2.575\sqrt{\frac{0.6267(0.3733)}{75}} = 0.4829[/tex]

To learn more about the z-distribution, you can take a look at https://brainly.com/question/16236451