Chapter 6, Section 2-CI, Exercise 081 Use the t-distribution to find a confidence interval for a mean μ given the relevant sample results. Give the best point estimate for μ, the margin of error, and the confidence interval. Assume the results come from a random sample from a population that is approximately normally distributed. A 95% confidence interval for μ using the sample results x¯=12.2, s=4.5, and n=30 Round your answer for the point estimate to one decimal place, and your answers for the margin of error and the confidence interval to two decimal places. point estimate =

Construct a confidence interval for P1 - P2 at the given level of confidence. X1 = 26, n, = 236, x2 = 30, n2 = 304, 90% confidence %3D The researchers are% confident the difference between the two population proportions, p, - P2, is between and (Use ascending order. Type an integer or decimal rounded to three decimal places as needed.)

In each of Exercises, we have presented a confidence interval (CI) for the difference, µ1 - µ2, between two population means. Interpret each confidence interval. 99% CI is from -20 to 15.

An IQ test is designed so that the mean is 100 and the standard deviation is 14 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 95​% confidence that the sample mean is within 7 IQ points of the true mean. Assume that σ=14 and determine the required sample size using technology. Then determine if this is a reasonable sample size for a real world calculation.

# E DII C A previous study gave (0.11, 0.23) as a confidence interval for p. Find the minimum sample size required to ensure that your estimate (p) will be within 0.01 of p with 99% confidence. IMPORTANT: Use a critical value that you found with your calculator (not from a table), and round it to 3 places after the decimal point before you plug it into a formula and perform your calculations. Do not round-off any other intermediate results. n = F3 Submit Question $ 4 R F F4 V % 5 T J G F5 6 B Y H F6 & 7 X U N F7 - * PrtScn 8 F8 M K Home 9 F9 O End L F10 P Pg Alt

n1=16 x‾1=124 s1=35   n2=12 x‾2=86 s2=31 Use this data to find the 98% confidence interval for the true difference between the population means. Assume that the population variances are not equal and that the two populations are normally distributed. Copy Data Step 2 of 3 :   Find the margin of error to be used in constructing the confidence interval. Round your answer to six decimal places. Step 3 of 3 : Please also find the high and low endpoints and round to four decimal points.

solve for the image below

In a large scale study of energy conservation in single family homes, 20 homes were randomly selected from homes built in a housing development in southern England. Ten of the houses, randomly selected from the 20 houses selected for the study, were constructed with standard levels of insulation (70 mm of roof insulation and 50 mm of insulation in the walls). The other 10 houses were constructed with extra insulation (120 mm of roof insulation and 100 mm of insulation in the walls). Each house was heated with a gas furnace and energy consumption was monitored for eight years. The data shown below give annual gas consumption in MWh for each of the 20 houses. Standard Insulation Extra Insulation 13.8 15.1 17.8 13.9 18.0 15.9 17.3 17.2 16.9 15.2 19.9 13.8 13.6 11.3 17.6 13.2 15.9 18.8 12.3 14.0 Sample means Sample Standard Deviation 16.31 14.84 2.38 2.12

An IQ test is designed so that the mean is 100 and the standard deviation is 10 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 99% confidence that the sample mean is within 4 IQ points of the true mean. Assume that σ=10 and determine the required sample size using technology. Then determine if this is a reasonable sample size for a real world calculation.

Use technology to construct the confidence intervals for the population variance o and the population standard deviation o. Assume the sample is taken from a normally distributed population. c= 0.90, s = 5.76, n = 26 The confidence interval for the population variance is ( ). (Round to two decimal places as needed.) The confidence interval for the population standard deviation is ( ). (Round to two decimal places as needed.)