Determine the point estimate of the population mean and margin of error for the confidence interval with lower bound 34 and upper bound: 42.

A cell phone manufacturer has hired you to estimate the population mean of the battery lifetimes for all phones of their latest model. You decide to measure battery lifetime by recording the time it takes for the battery charge to run out while a tester is streaming videos on the phones continuously. Then you select a random sample of 45 cell phones of the manufacturer's latest model and record their battery lifetimes. Assume that the population standard deviation of the battery lifetimes for that cell phone model (using your method of measurement) is 2.42 hours. Based on your sample, follow the steps below to construct a 95% confidence interval for the population mean of the battery lifetimes for all phones of the manufacturer's latest model. (If necessary, consult a list of formulas.) (a) Click on "Take Sample" to see the results from your random sample of 45 phones of the manufacturer's latest model. Take Sample Sample size: Number of phones Point estimate: 45 Sample mean Standard…

A researcher collected sample data for 16 women ages 18 to 24. The sample had a mean serum cholesterol level (measured in mg/100 mL) of 192.4, with a standard deviation of 9.6  Assuming that serum cholesterol levels for women ages 18 to 24 are normally distributed, find a 90% confidence interval for the mean serum cholesterol level of all women in this age group. Then find the lower limit and upper limit of the 90% confidence interval. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. Lower level: Upper Level:

A certain counselor wishes to compare the mean IQ scores of two different social groups. A random sample of 12group IQ scores1showed an average of85and a standard deviation offiftewhile a random sample chosen independently ofelegroup IQ scores2showed an average of 108and a standard deviation of13. Assuming that the populations of IQ scores for each of the groups follow a normal distribution and that the variances of these populations are equal, construct a confidence interval for the90%forμ₁ −μ₂, the difference between the meanµ₁group IQ scoresland the meanμgroup IQ scores2. Then find the lower limit and the upper limit of the confidence interval of the90%. - Carry out intermediate calculations using at least three decimal places. Round answers to at least two decimal places. (If necessary, you can refer to a list of formulas.) Lower limit: Upper limit: X Ś