Carla has 58 pencils what is the value of the digit of in this number

A manufacturer knows that their items have a normally distributed lifespan, with a mean of 5.5 years, and standard deviation of

Alina [70]

Answer:

If 24 items are picked at random, 8% of the time their mean life will be less than 5.156 years.

Step-by-step explanation:

To solve this question, we have to understand the normal probability distribution and the central limit theorem.

Normal probability distribution:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central limit theorem:

The Central Limit Theorem estabilishes that, for a random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sample means with size n of at least 30 can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$

In this problem, we have that:

$\mu = 5.5, \sigma = 1.2, n = 24, s = \frac{1.2}{\sqrt{24}} = 0.2449$

If 24 items are picked at random, 8% of the time their mean life will be less than how many years?

This is the value of X when Z has a pvalue of 0.08. So it is X when Z = -1.405.

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$-1.405 = \frac{X - 5.5}{0.2449}$

$X - 5.5 = -1.405*0.2449$

$X = 5.156$

If 24 items are picked at random, 8% of the time their mean life will be less than 5.156 years.

3 0

3 years ago

An ordinary (fair) die is a cube with the numbers 1 through 6 on the sides (represented by painted spots). Imagine that such a d

anygoal [31]

Answer:

The probability of event A is $\frac{7}{11}$ .

The probability of event B is $\frac{6}{11}$ .

Step-by-step explanation:

The sample space of rolling a fair six-sided dice is as follows:

S = {(1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6)

(2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6)

(3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6)

(4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6)

(5, 1), (5, 2), (5, 3), (5, 4), (5, 5), (5, 6)

(6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)}

Now consider the experiment of the computing the sum of the two rolls as follows:

X = {2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}

Number of total outcomes, N = 11.

The probability of an event E is the ratio of the number of favorable outcomes to the total number of outcomes.

$P(E)=\frac{n(E)}{N}$

The event A is defined as the sum is greater than 5.

The sample space of A is:

A = {6, 7, 8, 9, 10, 11, 12}

n (A) = 7

Compute the probability of event A as follows:

$P(A)=\frac{n(A)}{N}=\frac{7}{11}$

Thus, the probability of event A is $\frac{7}{11}$ .

The event B is defined as the sum is an even number.

The sample space of B is:

B = {2, 4, 6, 8, 10, 12}

n (B) = 6

Compute the probability of event B as follows:

$P(B)=\frac{n(B)}{N}=\frac{6}{11}$

Thus, the probability of event B is $\frac{6}{11}$ .

7 0

3 years ago

A car that travels along the highway to Denver at a steady speed. When it begins, it is 300 miles from Denver. After 3 hours, it

umka21 [38]

Answer: $y=-40x+300$

Step-by-step explanation:

This car follows a line, hence its motion can be modeled by the Line equation.

In fact, we already have two points of the line, if we call $x$ the time in hours and $y$ the traveled distance in miles:

Point 1: $(x_{1},y_{1})=(0,300)$

Since we are told the car's initial position is 300 miles in the time 0 h

Point 2: $(x_{2},y_{2})=(3,180)$

Since we are told the car's final position is 180 miles after 3h

Let's find the Slope $m$ :

$m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$

$m=-40$ This is the slope of the line

Now, the equation of the line is:

$y=mx+b$

We already know the slope, now we have to find the intersection point with the y-axis ( $b$ ) with any of the given points. Let's choose Point 1: $(x_{1},y_{1})=(0,300)$