An engineer randomly inspected 140 rural bridges in a state and found that 50 had serious...

An engineer randomly inspected 140 rural bridges in a state and found that 50 had serious problems. What is a 95% confidence interval for the proportion of bridges in the state with serious problems? (Show work)

Solutions

Expert Solution

We have given here,

x=50
n=140
Estimate for sample proportion

Level of significance is =1-0.95=0.05
Z critical value(using Z table)=1.96

orchestra answered 1 year ago

Next > < Previous

Related Solutions

A recent study on serious car accidents involving male drivers aged 18-24 found that 50% of...

A recent study on serious car accidents involving male drivers aged 18-24 found that 50% of the accidents were caused by excessive speed, 30% of the accidents caused by mobile phone use and 10% of the accidents involved the driver speeding and using his mobile phone. Hint: Use a Venn diagram to help answer the following questions about the serious car accidents What is the probability that an accident was caused by speeding alone? What is the probability that neither...

A survey of 25 randomly sampled judges employed by the state of Florida found that they...

A survey of 25 randomly sampled judges employed by the state of Florida found that they earned an average wage (including benefits) of $59.00 per hour. The sample standard deviation was $6.05 per hour. (Use t Distribution Table.) What is the best estimate of the population mean? Develop a 99% confidence interval for the population mean wage (including benefits) for these employees. (Round your answers to 2 decimal places.) How large a sample is needed to assess the population mean...

A survey of 25 randomly sampled judges employed by the state of Florida found that they...

A survey of 25 randomly sampled judges employed by the state of Florida found that they earned an average wage (including benefits) of $67.00 per hour. The sample standard deviation was $5.75 per hour. What is the best estimate of the population mean? Develop a 95% confidence interval for the population mean wage (including benefits) for these employees. (Round your answers to 2 decimal places.) How large a sample is needed to assess the population mean with an allowable error...

A survey of 20 randomly sampled judges employed by the state of Florida found that they...

A survey of 20 randomly sampled judges employed by the state of Florida found that they earned an average wage (including benefits) of $63.00 per hour. The sample standard deviation was $5.90 per hour. (Use t Distribution Table.) What is the best estimate of the population mean? Develop a 98% confidence interval for the population mean wage (including benefits) for these employees. (Round your answers to 2 decimal places.) Confidence interval for the population mean wage is between and How...

Students at a college randomly selected 217 student cars and found that they had ages with...

Students at a college randomly selected 217 student cars and found that they had ages with a mean of 7.89 years and a standard deviation of 3.67 years. They also randomly selected 152 faculty cars and found that they had ages with a mean of 5399 years and a standard deviation of 3.65 years. a) Using a 0.05 significance level, are student cars older than faculty cars? List: Define the parameters u1 and u2 Null and Alternative Hypothesis P-value Initial...

A meteorologist who sampled 35 randomly selected thunderstorms found that they had a mean speed of...

A meteorologist who sampled 35 randomly selected thunderstorms found that they had a mean speed of travel across a state of 16 miles per hour and a standard deviation of 1.5 miles per hour find a 98% confidence interval for the population mean travel speed for the thunderstorms across a state ( round to 1 decimal place) Find the margin of error ( round to 1 decimal place) if the meteorologist wants her estimate to be within 0.3 with 98%...

A bank randomly selected 249 checking account customers and found that 113 of them also had...

A bank randomly selected 249 checking account customers and found that 113 of them also had savings accounts at this same bank. Construct a 95% confidence interval for the true proportion of checking account customers who also have savings accounts. (Round your answers to three decimal places.) lower limit upper limit

A study of randomly selected Americans found that of 1,792 men, 244 had cardiovascular disease (CVD)...

A study of randomly selected Americans found that of 1,792 men, 244 had cardiovascular disease (CVD) and of 2,007 women, CVD was prevalent in 135 of them. Conduct a hypothesis test to see if CVD prevalence is higher among men than women in America. Let men be group 1 and women be group 2. A. Write the hypotheses for this test. B. What is the test statistic? C. What is the p-value? D. Using α = 0.05, decide whether or...

15. A Pew Poll in 2010, found that 50% of adults aged 25-29 had access to...

15. A Pew Poll in 2010, found that 50% of adults aged 25-29 had access to only a cell phone, while 40% had access to both a cellphone and landline and 10% had access to only a landline. We wish to conduct a Goodness of Fit Test to see if the results of a poll of a random sample of 130 adults aged 25-29 are significantly different from the 2010 poll results. The random sample of 130 adults found that...

Subjects