Question

Question 1

Arsenic is a toxic element found in nature, and it can accumulate in rice crops. In a study of arsenic in rice, a sample of n = 10 batches of brown rice grown in Texas had a mean concentration of 3.5 mg/kg of arsenic. The standard deviation of this sample was 0.16 mg/kg. If we use 3.5 mg/kg as an estimate of the average arsenic concentration for brown rice grown in Texas, what is the margin of error in a 95% confidence interval? (Assume the sample is symmetrically distributed with no outliers.)

	A.	0.03
	B.	0.11
	C.	0.20
	D.	0.09

Question 2

One form of pain management for primary osteoarthirtis (OA), a common type of arthritis, is to maintain a healthy weight. A 2010 clinical trial compared the pain levels of 192 participants randomly assigned to one of two low calorie diets: half were assigned to diet A and the other half were assigned to diet B. After an eight week period, 59 of those using diet A and 63 of the diet B participants reported decreased pain.

What is the pooled sample proportion of diets A and B who reported a decreased pain level?

	A.	0.50
	B.	0.635
	C.	0.615
	D.	0.656

Answer 1

Q1. Given n=10,

s=0.16

Since the the sample is symmetrically distributed with no outliers and population variance is umknown we used t critical value to find the the margin of error in a 95% confidence interval.

The margin of error in 95% confidence interval is:

Answer is B)

Q2. Given n1=96, n2=96

The choice is B)