1. A political candidate has asked you to conduct a poll to determine what percentage of people support her. If the candidate only wants a 4% margin of error at a 95% confidence level, what size of sample is needed? Give your answer in whole people.
Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 415 drivers and find that 286 claim to always buckle up. Construct a 95% confidence interval for the population proportion that claim to always buckle up. Use interval notation, for example, [1,5]
1)
without prior estimate, let
sample proportion , p̂ = 0.5
sampling error , E = 0.04
Confidence Level , CL= 0.95
alpha = 1-CL = 0.05
Z value = Zα/2 = 1.960 [excel
formula =normsinv(α/2)]
Sample Size,n = (Z / E)² * p̂ * (1-p̂) = (
1.960 / 0.04 ) ² *
0.50 * ( 1 - 0.50 ) =
600.2
so,Sample Size required=
601
2)
Level of Significance, α =
0.05
Number of Items of Interest, x =
286
Sample Size, n = 415
Sample Proportion , p̂ = x/n =
0.689
z -value = Zα/2 = 1.960 [excel
formula =NORMSINV(α/2)]
Standard Error , SE = √[p̂(1-p̂)/n] =
0.0227
margin of error , E = Z*SE = 1.960
* 0.0227 = 0.0445
95% Confidence Interval is
Interval Lower Limit = p̂ - E = 0.689
- 0.0445 = 0.6446
Interval Upper Limit = p̂ + E = 0.689
+ 0.0445 = 0.7337
95% confidence interval is (
0.6446 < p < 0.7337
)
1. A political candidate has asked you to conduct a poll to determine what percentage of...
Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 393 drivers and find that 305 claim to always buckle up. Construct a 87% confidence interval for the population proportion that claim to always buckle up. Use interval notation, for example, [1,5]
Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 393 drivers and find that 305 claim to always buckle up. Construct a 87% confidence interval for the population proportion that claim to always buckle up. Use interval notation, for example, [1,5]
FYI... The professor usually prefers TI calculator solutions, but I'd need to see the steps from very basic please. Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 388 drivers and find that 314 claim to always buckle up. Construct a 82 % confidence interval for the population proportion that claim to always buckle up. Use interval notation, for example, (1,5]
A political candidate has asked you to conduct a poll to determine what percentage of people support her. If the candidate only wants a 4% margin of error at a 95% confidence level, what size of sample is needed? Hint: Textbook Video [+]
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A political candidate has asked you to conduct a poll to determine what percentage of people support her. If the candidate only wants a 5% margin of error at a 95% confidence level, what is the minimum sample size needed for the study? Give your answer as a whole number.
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Please show steps in a it84 calculator Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 387 drivers and find that 302 claim to always buckle up. Construct a 90% confidence interval for the population proportion that claim to always buckle up. Use interval notation, for example, [1,5] Box 1: Enter your answer using interval notation. Example: [2.1,5.6172) Use U for union to combine intervals. Example:...
PLEASE HELP AND SHOW WORK OR CALCULATOR WAY ON TI84 Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 390 drivers and find that 296 claim to always buckle up. Construct a 96% confidence interval for the population proportion that claim to always buckle up. Use interval notation, for example, [1,5] Box 1: Enter your answer using interval notation. Example: [2.1,5.6172) Use U for union to...