A large company produces an equal number of brand-name lightbulbs and generic lightbulbs. The director believes that the proportion of brand-name lightbulbs that are defective is not equal to the proportion of generic lightbulbs that are defective. Therefore, the director wants to estimate the average of the two proportions. To estimate the proportion of brand-name lightbulbs that are defective, a simple random sample of 400 brand-name lightbulbs is taken and 44 are found to be defective. Let X represent the number of brand-name lightbulbs that are defective in a sample of 400, and let PX represent the proportion of all brand-name lightbulbs that are defective. It is reasonable to assume that X is a binomial random variable.
- Calculate the standard error of (px+py /2)
I know that the standard error for px is 0.0156 and py is 0.0219. Im not sure where to go from there.
1 answer
The standard error of (px+py /2) is (0.0156 + 0.0219) / 2 = 0.0188.
1 answer