A researcher wishes to estimate, with 9999% confidence, the population proportion of adults who think Congress is doing a goo
d or excellent job. Her estimate must be accurate within 44% of the true proportion. (a) No preliminary estimate is available. Find the minimum sample size needed. (b) Find the minimum sample size needed, using a prior study that found that 2222% of the respondents said they think Congress is doing a good or excellent job. (c) Compare the results from parts (a) and (b). (a) What is the minimum sample size needed assuming that no prior information is available? nequals=nothing (Round up to the nearest whole number as needed.)
1 answer:
Answer:
a: 1037 is the minimum sample size needed
b: 712 is the minimum sample size needed
Step-by-step explanation:
We need to use the formula for minimum sample size of a proportion when a sample proportion is known.
The level of confidence is 99%, which has a corresponding z-value of 2.575.
We know the desired error is 4%, or 0.04.
Part a: We have no prior estimate. See attached photo for calculation
Part b:
We know p-hat = 0.22. Therefore q-hat = 1 - 0.22 = 0.78
See the attached photo for the calculation of the minimum sample size
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Answer:
16 feet
Step-by-step explanation:
The length of the ladder=20 feet
Distance from the base of the ladder to the house = 12 feet
You will notice that a wall is vertical and the ladder makes an angle with the horizontal ground(making it the hypotenuse). This is a right triangle problem.
To find the how far up the house can the ladder can reach, we simply find the third side of the right triangle.
From Pythagoras theorem
The third side of the right triangle is 16. Therefore the ladder leans 16 feet from the ground.