A sample of 45 small generators produce fumes that was observed to be 700 ppm with a standard deviation of 165. a) Calculate and interpret 95% two-sided confidence interval for true average amount of fumes for a population of all similar generatorsb) Assume the intial observations were based on an initial estimate of 170 for the value of the sample standard deviation. What is the necessary sample size that would result in an interval width of 40 ppm for a confidence level of 95%   Show all work

The quality control manager at a light bulb factory needs to estimate the mean life of a large shipment of light bulbs. The standard deviation is 108 hours. A random sample of 64 light bulbs indicated a sample mean life of 370 hours. Complete parts (a) through (d) below. a. Construct a 99% confidence interval estimate for the population mean life of light bulbs in this shipment. The 99% confidence interval estimate is from a lower limit of hours to an upper limit of hours. (Round to one decimal place as needed.) b. Do you think that the manufacturer has the right to state that the lightbulbs have a mean e of 430 hours? Explain. Based on the sample data, the manufacturer V the right to state that the lightbulbs have a mean life of 430 hours. A mean of 430 hours is V standard errors V the sample mean, so it is V that the lightbulbs have a mean life of 430 hours. c. Must you assume that the population light bulb life is normally distributed? Explain. O A. No, since o is known, the…

The number of eggs laid by a particular breed of hen during their laying season has a standard deviation of 17.1. Suppose a sample of 48 hens are observed for an entire laying season, and the number of eggs they each lay is counted. Calculate the margin of error for constructing a 95% confidence interval for the mean number of eggs laid, assuming normality.

There was a study was conducted and two types of engines, A and B, were compared. Fifty experiments were performed using engine A and 75 using B. The average gas mileage for A was 36 mpg, and 42 mpg for B.  Assume population standard deviations for A and B are respectively 6 and  8. a) What is the point estimate? b) What is the margin of error? c) Construct the 95% confidence interval for the difference of population mean gas mileages for negines A and B