A veterinarian collects a random sample of 40 cats that she has treated over the years and indicated the number of years each cat lived. Ten of the forty cats lived to be over 11 years old.
1. Use the Empirical Rule to construct a 99.7% confidence interval of the proportion (round to three decimal places) of all cats that will live to be more than 11 years old.
2. What sample size should the veterinarian use to achieve a margin of error of no more than 8% for the 99.7% confidence interval using the Empirical Rule? Use p=0.5 since we do not know the exact population proportion.

Respuesta :

Answer:

1. 0.047, 0.453

2. 343

Step-by-step explanation:

The confidence interval regarding the veterinarian will be (0.045, 0.455).

How to depict the confidence interval?

Sample success = 10

Sample size = 40

Pt estimate = 10/40 = 0.25

Standard error = 0.0685

The corresponding interval is (0.045, 0.455).

The sample size that the veterinarian should use to achieve a margin of error will be:

Margin of error = 0.08

Critical Z = 3.0

Estimated proportion = 0.5

Sample size = p × (1-p) × (z/e)²

= 0.5 × (1-0.5) × (3/0.08)²

= 352

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