Question

Toys for make-believe play make-up may contain high levels of flavors and/or fragrances that can cause an allergic reaction leading to skin blistering in sensitive individuals. To get an estimate of how much fragrance a certain toy lip gloss product contains, we select a simple random sample of 20 tubes of the product and measure the amount of fragrance oil contained in each tube.

Assuming the dataset meets all conditions for the validity of the t inferences, which is the best t procedure to use in this instance?

	A.	It won't help to do a confidence interval if we don't know how much fragrance causes blisters.
	B.	a two-sample t confidence interval.
	C.	a matched pairs t confidence interval.
	D.	a one-sample t confidence interval

A study examined the effect of protein consumption on weight gain in rats. Investigators took 18 female rats and randomly assigned 9 to a low-protein diet and 9 to a high-protein diet. After 60 days, the weight gained by each rat was recorded (in grams).

Which of the following would lead us to believe that the t procedures were NOT appropriate to use here?

	A.	The population standard deviations were not known.
	B.	The distributions of the datasets were skewed or had outliers.
	C.	The experiment wasn’t double-blinded.
	D.	Only female rats were used.

Answer 1