A researcher wants to conduct a study to see if cell phones cause headaches. The researcher finds 30 individuals who use cell phones regularly and 30 that do not. Each of the 60 individuals are given a questionnaire designed to determine headache frequency. If the 60 individuals did not know they were participating in the study, which statement about the study is correct? a. It is an experiment where cell phone habits is a blocking variable.
b. It is an observational study.
c. It is a matched-pairs design.
d. It is a randomized experiment.
e. It is a double-blind study.

The table above shows approximate conversions from gallons to liters. what is the value of x?

Someone answer this asap rn 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)) =

Can some one me with these questions