Math  /  Data & Statistics

QuestionThe and arranged in groups of three. The random variable xx is the number in the group who say that they would feel comfortable in a self-driving vehicle. Determine whether a probability distribution is given. If a probability distribution is given, find its mean and standard deviation. If a probability distribution is not given, identify the requirements that are not satisfied. \begin{tabular}{c|c} \hline x\mathbf{x} & P(x)\mathbf{P}(\mathbf{x}) \\ \hline 0 & 0.362 \\ \hline 1 & 0.443 \\ \hline 2 & 0.172 \\ \hline 3 & 0.023 \\ \hline \end{tabular}
Does the table show a probability distribution? Select all that apply. A. Yes, the table shows a probability distribution. B. No, not every probability is between 0 and 1 inclusive. C. No, the random variable x's number values are not associated with probabilities. D. No, the sum of all the probabilities is not equal to 1 . E. No, the random variable xx is categorical instead of numerical.
Find the mean of the random variable xx. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. μ=\mu= \square adult(s) (Round to one decimal place as needed.) B. The table does not show a probability distribution.

Studdy Solution

STEP 1

What is this asking? We're checking if a table represents a valid probability distribution, and if it does, we need to calculate its mean and standard deviation. Watch out! A probability distribution must have probabilities between 0 and 1 that add up to 1, and the variable must be numerical.

STEP 2

1. Check if it's a probability distribution
2. Calculate the mean
3. Calculate the standard deviation

STEP 3

Let's **look** at the given probabilities: 0.3620.362, 0.4430.443, 0.1720.172, and 0.0230.023.
Are they all between 00 and 11?
Yes! Awesome!

STEP 4

Now, let's **add** them all up: 0.362+0.443+0.172+0.023=10.362 + 0.443 + 0.172 + 0.023 = 1.
Perfect! They add up to 11, just like they should for a probability distribution.

STEP 5

The random variable xx represents the number of adults in a group who are comfortable with self-driving vehicles.
This is a numerical value, so we're good here.

STEP 6

Since all the conditions are met, we can **conclude** that the table *does* show a probability distribution.

STEP 7

Remember, the mean (μ\mu) of a probability distribution is calculated as: μ=xP(x) \mu = \sum x \cdot P(x)

STEP 8

Let's **apply** this formula to our table: μ=(00.362)+(10.443)+(20.172)+(30.023) \mu = (0 \cdot 0.362) + (1 \cdot 0.443) + (2 \cdot 0.172) + (3 \cdot 0.023) μ=0+0.443+0.344+0.069 \mu = 0 + 0.443 + 0.344 + 0.069 μ=0.856 \mu = 0.856

STEP 9

So, the **mean** is 0.8560.856.
This means that in a random group of three adults, we expect, on average, about 0.8560.856 of them to be comfortable with self-driving vehicles.

STEP 10

The standard deviation (σ\sigma) is calculated as: σ=(xμ)2P(x) \sigma = \sqrt{\sum (x - \mu)^2 \cdot P(x)}

STEP 11

Using our calculated mean (μ=0.856\mu = 0.856): σ=(00.856)20.362+(10.856)20.443+(20.856)20.172+(30.856)20.023 \sigma = \sqrt{(0 - 0.856)^2 \cdot 0.362 + (1 - 0.856)^2 \cdot 0.443 + (2 - 0.856)^2 \cdot 0.172 + (3 - 0.856)^2 \cdot 0.023} σ=0.265+0.009+0.213+0.101 \sigma = \sqrt{0.265 + 0.009 + 0.213 + 0.101} σ=0.588 \sigma = \sqrt{0.588} σ0.767 \sigma \approx 0.767

STEP 12

The **standard deviation** is approximately 0.7670.767.
This tells us how spread out the data is around the mean.

STEP 13

The table *does* represent a probability distribution (A).
The mean is 0.8560.856 adults (A).
The standard deviation is approximately 0.7670.767.

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