Aresearcher is planning to construct a one-sample z? confidence interval for a population mean ? . select the statements that would lead to a smaller margin of error, assuming the other factors remain the same.

a) the population standard deviation turns out to be higher than expected.

b) the researcher increases the sample size.

c) the researcher lowers the confidence level.

d) the researcher decreases the sample size.

e) the population standard deviation turns out to be lower than expected.

f) the researcher raises the confidence level.

Someone answer asap for ! a discount store’s prices are 25% lower than department store prices. the function c(x) = 0.75x can be used to determine the cost c, in dollars, of an item, where x is the department store price, in dollars. if the item has not sold in one month, the discount store takes an additional 20% off the discounted price and an additional $5 off the total purchase. the function d(y) = 0.80y - 5 can be used to find d, the cost, in dollars, of an item that has not been sold for a month, where y is the discount store price, in dollars. create a function d(c(x)) that represents the final price of an item when a costumer buys an item that has been in the discount store for a month. d(c(x)) =