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A U.S. Coast Guard survey of 500 small boats in the Cape Cod area found 195 in violation of one or more
safety regulations.
a. What is the value of the point estimate?
b. What is the critical value you will use for a 95% confidence interval?
C.
What is the value of the standard error?
d. What is the value of the margin of error?
e. State the lower and upper bounds for a 95% confidence interval.
f. State a conclusion, in context.


Sagot :

Using the information given, it is found that:

a) 0.39

b) z = 1.96

c) s = 0.0218

d) M = 0.0428

e)

  • The lower bound is 0.3472.
  • The upper bound is 0.4328.

f) The 95% confidence interval is (0.3472, 0.4328), which means that we are 95% sure that the true proportion of boats who are in violation of one or more  safety regulations is (0.3472, 0.4328).

Item a:

The point estimate is the sample proportion, hence:

[tex]\pi = \frac{195}{500} = 0.39[/tex]

Item b:

95% confidence level, hence [tex]\alpha = 0.95[/tex], the critical value z is the value of Z that has a p-value of [tex]\frac{1+0.95}{2} = 0.975[/tex], so [tex]z = 1.96[/tex].

Item c:

The standard error is:

[tex]s = \sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

For this problem, [tex]\pi = 0.39, n = 500[/tex], hence:

[tex]s = \sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

[tex]s = \sqrt{\frac{0.39(0.61)}{500}}[/tex]

[tex]s = 0.0218[/tex]

Item d:

The margin of error is:

[tex]M = zs[/tex]

In this problem, [tex]z = 1.96, s = 0.0218[/tex], hence:

[tex]M = zs = 1.96(0.0218) = 0.0428[/tex]

Item e:

The lower bound is:

[tex]\pi - M = 0.39 - 0.0428 = 0.3472[/tex]

The upper bound is:

[tex]\pi + M = 0.39 + 0.0428 = 0.4328[/tex]

The lower bound is 0.3472.

The upper bound is 0.4328.

Item f:

The 95% confidence interval is (0.3472, 0.4328), which means that we are 95% sure that the true proportion of boats who are in violation of one or more  safety regulations is (0.3472, 0.4328).

A similar problem is given at https://brainly.com/question/15136737