Concept explainers
Effectiveness of a New Drug. As part of the U.S. Food and Drug Administration’s approval process, a new rheumatoid arthritis drug was compared to a placebo. The randomized, double-blind study with 482 patients showed that 41% of those given the new drug had a decrease in symptoms, while 19% of those given the placebo experienced improvement (Western Journal of Medicine).
a. Which patients were in the treatment group and the control group?
b. Do the results appear to offer evidence that the new drug was effective? Why or why not?
c. Do the results appear to indicate that a placebo effect was present in these trials? Explain.
d. If you were on the panel deciding whether to approve the new drug, how would you vote based on this study? Explain your reasoning.
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USING AND UNDERSTANDING MATHEMATICS W/
- 4. (i) Let a discrete sample space be given by N = {W1, W2, W3, W4}, and let a probability measure P on be given by P(w1) = 0.2, P(w2) = 0.2, P(w3) = 0.5, P(wa) = 0.1. Consider the random variables X1, X2 → R defined by X₁(w1) = 1, X₁(w2) = 2, X2(w1) = 2, X2 (w2) = 2, Find the joint distribution of X1, X2. (ii) X1(W3) = 1, X₁(w4) = 1, X2(W3) = 1, X2(w4) = 2. [4 Marks] Let Y, Z be random variables on a probability space (, F, P). Let the random vector (Y, Z) take on values in the set [0, 1] x [0,2] and let the joint distribution of Y, Z on [0, 1] x [0,2] be given by 1 dPy,z (y, z) ==(y²z+yz2) dy dz. harks 12 Find the distribution Py of the random variable Y. [8 Marks]arrow_forwardNeed help answering wuestionarrow_forwardFor the following function, find the full power series centered at x = 0 and then give the first 5 nonzero terms of the power series and the open interval of convergence. f(x) = Σ| n=0 9 f(x) = 6 + 4x f(x)− + + + ++··· The open interval of convergence is: ☐ (Give your answer in help (intervals) .)arrow_forward
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- Let X be a random variable with the standard normal distribution, i.e.,X has the probability density functionfX(x) = 1/√2π e^-(x^2/2)2 .Consider the random variablesXn = 20(3 + X6) ^1/2n e ^x^2/n+19 , x ∈ R, n ∈ N.Using the dominated convergence theorem, prove that the limit exists and find it limn→∞E(Xn)arrow_forwardLet X be a discrete random variable taking values in {0, 1, 2, . . . }with the probability generating function G(s) = E(sX). Prove thatVar(X) = G′′(1) + G′(1) − [G′(1)]2.[5 Marks](ii) Let X be a random variable taking values in [0,∞) with proba-bility density functionfX(u) = (5/4(1 − u^4, 0 ≤ u ≤ 1,0, otherwise. Let y =x^1/2 find the probability density function of Yarrow_forward14 14 4. The graph shows the printing rate of Printer A. Printer B can print at a rate of 25 pages per minute. How does the printing rate for Printer B compare to the printing rate for Printer A? The printing rate for Printer B is than the rate for Printer A because the rate of 25 pages per minute is than the rate of for Printer A. pages per minute RIJOUT 40 fy Printer Rat Number of Pages 8N WA 10 30 20 Printer A 0 0 246 Time (min) Xarrow_forward
- 2. y 1 Ο 2 3 4 -1 Graph of f x+ The graph gives one cycle of a periodic function f in the xy-plane. Which of the following describes the behavior of f on the interval 39 x < 41 ? (Α B The function f is decreasing. The function f is increasing. The function f is decreasing, then increasing. D The function f is increasing, then decreasing.arrow_forwardDepth (feet) 5- 4- 3- 2. WW www 1 D B 0 10 20 30 40 50 60 70 80 Time (hours) x A graph of the depth of water at a pier in the ocean is given, along with five labeled points A, B, C, D, and E in the xy-plane. For the time periods near these data points, a periodic relationship between depth of water, in feet, and time, in hours, can be modeled using one cycle of the periodic relationship. Based on the graph, which of the following is true? B C The time interval between points A and B gives the period. The time interval between points A and C gives the period. The time interval between points A and D gives the period. The time interval between points A and E gives the period.arrow_forwardA certain type of machine produces a number of amps of electricity that follows a cyclic, periodically increasing and decreasing pattern. The machine produces a maximum of 7 amps at certain times and a minimum of 2 amps at other times. It takes about 5 minutes for one cycle from 7 amps to the next 7 amps to occur. Which of the following graphs models amps as a function of time, in minutes, for this machine? A B C D Amps M 3 4 5 678 Minutes Amps w 3 4 5 6 7 8 Minutes 8 Amps- 6+ Amps y 2345678 Minutes 456 8 Minutesarrow_forward
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