Chapter 3: Q7E (page 117)
Suppose, as in Exercise 7 of Sec. 3.2, that a random variable X has a uniform distribution on the interval [−2, 8]. Find and sketch the c.d.f. of X.
Short Answer

/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}
Learning Materials
Features
Discover
Chapter 3: Q7E (page 117)
Suppose, as in Exercise 7 of Sec. 3.2, that a random variable X has a uniform distribution on the interval [−2, 8]. Find and sketch the c.d.f. of X.

All the tools & learning materials you need for study success - in one app.
Get started for free
Question:Consider the clinical trial of depression drugs in Example2.1.4. Suppose that a patient is selected at random from the 150 patients in that study and we recordY, an indicator of the treatment group for that patient, andX, an indicator of whether or not the patient relapsed. Table 3.3contains the joint p.f. ofXandY.
Response(X) | Treatment Group(Y) | |||
Impramine(1) | Lithium(2) | Combination(3) | Placebo(4) | |
Relapse(0) | 0.120 | 0.087 | 0.146 | 0.160 |
No relapse(1) | 0.147 | 0.166 | 0.107 | 0.067 |
a. Calculate the probability that a patient selected at random from this study used Lithium (either alone or in combination with Imipramine) and did not relapse.
b. Calculate the probability that the patient had a relapse(without regard to the treatment group).
Suppose that a person’s score X on a mathematics aptitude test is a number between 0 and 1, and that his score Y on a music aptitude test is also a number between 0 and 1. Suppose further that in the population of all college students in the United States, the scores X and Y are distributed according to the following joint pdf:
\(f\left( {x,y} \right)\left\{ \begin{aligned}\frac{2}{5}\left( {2x + 3y} \right)for0 \le x \le 1 and 0 \le y \le 1\\0 otherwise\end{aligned} \right.\)
a. What proportion of college students obtain a score greater than 0.8 on the mathematics test?
b. If a student’s score on the music test is 0.3, what is the probability that his score on the mathematics test will be greater than 0.8?
c. If a student’s score on the mathematics test is 0.3, what is the probability that his score on the music test will be greater than 0.8?
Let Xbe a random variable for which the p.d.f. is as in Exercise 5. After the value ofXhas been observed, letYbe the integer closest toX. Find the p.f. of the random variableY.
Let X have the uniform distribution on the interval, and let prove that \({\bf{cX + d}}\) it has a uniform distribution on the interval \(\left[ {{\bf{ca + d,cb + d}}} \right]\)
Suppose that a Markov chain has four states 1, 2, 3, 4, and stationary transition probabilities as specified by the following transition matrix
\(p = \left[ {\begin{array}{*{20}{c}}{\frac{1}{4}}&{\frac{1}{4}}&0&{\frac{1}{2}}\\0&1&0&0\\{\frac{1}{2}}&0&{\frac{1}{2}}&0\\{\frac{1}{4}}&{\frac{1}{4}}&{\frac{1}{4}}&{\frac{1}{4}}\end{array}} \right]\):
a.If the chain is in state 3 at a given timen, what is the probability that it will be in state 2 at timen+2?
b.If the chain is in state 1 at a given timen, what is the probability it will be in state 3 at timen+3?
What do you think about this solution?
We value your feedback to improve our textbook solutions.