/*! 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} Problem 55 The range of the random variable... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

The range of the random variable \(X\) is \([0,1,2,3, x]\), where \(x\) is unknown. If each value is equally likely and the mean of \(X\) is \(6,\) determine \(x\).

Short Answer

Expert verified
The unknown value \(x\) is 24.

Step by step solution

01

Identify the Given Values

The possible values that the random variable \(X\) can take are \([0, 1, 2, 3, x]\). The mean of \(X\) is given as \(6\). We need to determine the unknown value \(x\) such that these five values have a mean of \(6\).
02

Apply the Mean Formula

The mean \(\mu\) of a set of equally likely values is the sum of those values divided by the number of values. For set \([0, 1, 2, 3, x]\), we have:\[ \mu = \frac{0 + 1 + 2 + 3 + x}{5} = 6 \]
03

Solve for the Unknown \(x\)

Solve the equation obtained in Step 2 for \(x\):\[ \frac{0 + 1 + 2 + 3 + x}{5} = 6 \]This simplifies to:\[ \frac{6 + x}{5} = 6 \]
04

Clear the Fraction

Multiply both sides by 5 to eliminate the fraction:\[ 6 + x = 30 \]
05

Isolate \(x\)

Subtract 6 from both sides to solve for \(x\):\[ x = 30 - 6 \]
06

Conclude the Solution

The solution is \(x = 24\). Thus, the unknown value in the range of \(X\) is \(24\).

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Equally Likely Values
When talking about random variables with equally likely values, it means that each possible outcome has the same probability of occurring. In the example given, the random variable \(X\) can take the values \([0,1,2,3,x]\), each with equal probability. This kind of situation often arises in contexts like rolling a fair die, flipping a balanced coin, or drawing cards from a well-shuffled deck.

In practical terms, having equally likely values simplifies calculations because the mean or average becomes easier to determine by merely summing up all the possible outcomes and dividing by their count. For instance, if you know that all possible results are perfectly balanced in likelihood, you don't need additional probabilities to calculate an average.

This concept is crucial for determining averages in uniformly distributed data, especially when you're looking at theoretical data or experiments where perfect balance is assumed.
Mean of a Distribution
The mean, or expected value, of a distribution tells us where the center of the data lies. It's a central measure used to summarize the entire set of data with a single number.

In our exercise, knowing the mean of the random variable \(X\) is particularly useful in solving for the unknown value \(x\). The formula to determine the mean \(\mu\) in cases of equally likely values is:
  • Sum all the possible values.
  • Divide the sum by the number of those values.
For the values \([0, 1, 2, 3, x]\), applying the mean formula produces:\[ \mu = \frac{0 + 1 + 2 + 3 + x}{5} = 6 \]By organizing equations like this, we can unlock the potential to solve for "unknowns" using the mean value as an anchor.

Understanding how to manipulate this average helps solidify the concept of the mean beyond mere calculation, allowing students to engage with real-world data similarly.
Solving for Unknown Variables
Finding unknown variables involves algebraic manipulation, and is a fundamental skill in mathematics. In our exercise, the unknown variable \(x\) is part of a group where each number contributes equally to the mean value. This provides a direct relation between the known mean and the unknown value.

To solve for \(x\), set up an equation where the sum of all possible values, divided by their number, equals the mean:\[ \frac{0 + 1 + 2 + 3 + x}{5} = 6 \]By first multiplying both sides by 5 to clear the fraction:\[ 6 + x = 30 \]You can then isolate \(x\) by subtracting 6 from both sides:\[ x = 30 - 6 \]Resulting in:\[ x = 24 \]This step-by-step approach makes it much easier to handle unknowns systematically and is beneficial for developing strong problem-solving capabilities. Understanding how to find unknowns is not just about completing a task; it teaches students how mathematical tools can describe and solve real-world phenomena.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A fault-tolerant system that processes transactions for a financial services firm uses three separate computers. If the operating computer fails, one of the two spares can be immediately switched online. After the second computer fails, the last computer can be immediately switched online. Assume that the probability of a failure during any transaction is \(10^{-8}\) and that the transactions can be considered to be independent events. (a) What is the mean number of transactions before all computers have failed? (b) What is the variance of the number of transactions before all computers have failed?

Assume that 20 parts are checked each hour and that \(X\) denotes the number of parts in the sample of 20 that require rework. Parts are assumed to be independent with respect to rework. (a) If the percentage of parts that require rework remains at \(1 \%\), what is the probability that hour 10 is the first sample at which \(X\) exceeds \(1 ?\) (b) If the rework percentage increases to \(4 \%,\) what is the probability that hour 10 is the first sample at which \(X\) exceeds \(1 ?\) (c) If the rework percentage increases to \(4 \%,\) what is the expected number of hours until \(X\) exceeds \(1 ?\)

Assume that each of your calls to a popular radio station has a probability of 0.02 of connecting, that is, of not obtaining a busy signal. Assume that your calls are independent. (a) What is the probability that your first call that connects is your tenth call? (b) What is the probability that it requires more than five calls for you to connect? (c) What is the mean number of calls needed to connect?

The number of pages in a PDF document you create has a discrete uniform distribution from five to nine pages (including the end points). What are the mean and standard deviation of the number of pages in the document?

In a clinical study, volunteers are tested for a gene that has been found to increase the risk for a disease. The probability that a person carries the gene is 0.1 . (a) What is the probability four or more people will have to be tested before two with the gene are detected? (b) How many people are expected to be tested before two with the gene are detected?

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.