Solve the problem.In a study of 135 women, roughly half took estrogen as well as calcium and vitamin D supplements and received regular dental checkups. The remaining women received the supplements and the checkups but substituted a sugar pill for the estrogen. Those who received the estrogen had an average 3.6 percent gain in bone density compared to a 0.2 percent bone density improvement in those taking the sugar pill. This study can best be described as
A. a survey using quota sampling.
B. a controlled placebo experiment.
C. a census.
D. a survey using simple random sampling.
E. the placebo effect.
Answer: B
Mathematics
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Perform the operation and reduce the answer to lowest terms.3
? 
A. 
B. 
C. 
D. 1
Mathematics
Write the Hindu-Arabic numeral for the given Egyptian numeral.
A. 245 B. 240,005 C. 2405 D. 2,000,045
Mathematics
Evaluate the expression.|5 - 10| + |11 + 5|
A. -21 B. -11 C. 11 D. 21
Mathematics
Complete the square for the binomial. Then factor the resulting perfect square trinomial.x2 - 7x
A. x2 - 7x + 
= 
2
B. x2 - 7x - 
= 
2
C. x2 - 7x + 
= 
2
D. x2 - 7x + 49 = (x - 7)2
Mathematics