5.7.9. In a certain part of a city, the average price of homes in 20oo was...
In a random sample of 100 homes in a certain city, it is found that 10 are heated by oil. (a) Find a 92% confidence interval for the true proportion of homes in the city that are heated with oil. (b) How large would the sample have to be in order to have a standard error that is 0.003 or lower?
The average natural gas bill for a random sample of 21 homes in a certain city during the month of March was $311.90 with a sample standard deviation of $51.60. What is the standard error of the mean for this sample? A. 11.26 B. 8.20 C. 9.93 D. 14.74
The average price for new mobile homes is known to be distributed with a population standard deviation of 300. If a random sample of 36 homes resulted in a sample mean of 45,000, obtain a 90% confidence interval.
A travel website would like to estimate the difference between the average rental price of a car with automatic transmission versus the average rental price of a car with manual transmission at a certain airport. The table below shows the average one-week rental prices for two random samples, as well as the population standard deviations and sample sizes for each type of car. Complete parts a and b. Sample mean Sample size Population standard deviation Automatic $417.50 55 $24 Manual...
o A travel website would like to estimate the difference between the average rental price of a car with automatic transmission versus the average rental price of a car with manual transmission at a certain airport. The table below shows the average one week rental prices for two random samples, as well as the population standard deviations and sample sizes for each type of car. Complete parts a and b. Sample mean Sample size Population standard deviation Automatic $398.20 50...
An investigator compares the durability of two different compounds used in the manufacture of a certain automobile brake lining. A sample of 259 brakes using Compound 1 yields an average brake life of 47,112 miles. A sample of 218 brakes using Compound 2 yields an average brake life of 30,864 miles. Assume that the population standard deviation for Compound 1 is 1681 miles, while the population standard deviation for Compound 2 is 1627 miles. Determine the 98% confidence interval for...
The average price of homes sold in the U.S. in the past year was $220,000. A random sample of 81 homes sold this year showed an average price of $210,000. It is known that the standard deviation of the population is $36,000. At 95% confidence test to determine if there has been a significant decrease in the average price homes. a.State the null and alternative hypotheses to be tested. b.Compute the test statistic. c.Compute the p-value. d.What do you conclude?
As part of a real estate companys study, the selling prices of 50 homes in a particular neighborhood were gathered. The sample mean price was $234,000. Assume that the population standard deviation is known to be $28500. Find a 95% confidence interval for the population mean selling price of all homes in this ne ghborhood. State the error bound used in your calculation Which distribution should be used to hnd the confidence interval? The standard normal distribution should be used...
Two random samples are selected from two independent populations. A summary of the samples sizes, sample means, and sample standard deviations is given below: n1=39, x¯1=57, s1=5.8 n2=50, x¯2=74.2 ,s2=10 Find a 98% confidence interval for the difference μ1−μ2 of the means, assuming equal population variances. Confidence Interval =
Analyses of drinking water samples for 100 homes in each of two different sections of a city gave the following means and standard deviations of lead levels (in parts per million): Section 1: n1 = 100, x¯1 = 34.1, s1 = 5.9, Section 2: n2 = 100, x¯2 = 36.0, s2 = 6.0. (a) Calculate the test statistic and its p-value to test for a difference in the two population means. Use the p-value to evaluate the statistical significance of...