Why is the relationship between distance and time linear?

Suppose a batch of metal shafts produced in a manufacturing company have a population standard deviation of 1.3 and a mean diame

lbvjy [14]

Answer:

54.86% probability that the mean diameter of the sample shafts would differ from the population mean by more than 0.1 inches

Step-by-step explanation:

To solve this question, we need 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 normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this problem, we have that:

$\mu = 208, \sigma = 1.3, n = 60, s = \frac{1.3}{\sqrt{60}} = 0.1678$

What is the probability that the mean diameter of the sample shafts would differ from the population mean by more than 0.1 inches

Lesser than 208 - 0.1 = 207.9 or greater than 208 + 0.1 = 208.1. Since the normal distribution is symmetric, these probabilities are equal, so we find one of them and multiply by 2.

Lesser than 207.9.

pvalue of Z when X = 207.9. So

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

By the Central Limit Theorem

$Z = \frac{207.9 - 208}{0.1678}$

$Z = -0.6$

$Z = -0.6$ has a pvalue of 0.2743

2*0.2743 = 0.5486

54.86% probability that the mean diameter of the sample shafts would differ from the population mean by more than 0.1 inches

6 0

3 years ago

Lia must work at least 5 hours per week in her family’s restaurant for $8 per hour. She also does yard work for $12 per hour. Li

vladimir2022 [97]

As the question states, let r be the number of hours worked at the restaurant, and y be the number of hours of yard work.
We know that she can only work a maximum of 15 hours per work total, and that at she must work at least 5 hours in the restaurant.
Therefore:
r + y ≤ 15
r ≥ 5
We also know that she wants to earn at least 120 dollars, earning $8/hr in the restaurant and $12/hr in the yard:
8r + 12y ≥ 120

What is the maximum of hours Lia can work in the restaurant and still make at leas 120 hours?
Lia's parents won't let her work more than 15 hours, so we know that the answer won't be higher than 15.
If she worked all 15 hours in the restaurant, she would make 8*15 = 120.
The maximum number of hours she can work in the restaurant is therefore 15 hours

What is the maximum amount of money Lia can earn in a week?
Lia has to work a minimum of 5 hours in the restaurant. She makes more money doing yard work, so she should devote the rest of her available work hours to yard work.
That means that, given her 15 hour work limit, she will maximize her income by working 5 hours in the restaurant and 10 hours in the yard.
5*8 + 10*12 = 40 + 120 = 160
The most she can make is 160 dollars, working 5 hours in the restaurant and 10 hours in the yard

7 0

3 years ago

Not sure how to find the answer

Masja [62]

Answer:

Que curso es

Sten

3 0

3 years ago

Find the value of k so that the graph of 13y + kx = 4 and the line containing the points (5, -8) and (2, 4) are parallel.

guajiro [1.7K]

the graph of 13y + kx = 4 and the line containing the points (5, -8) and (2, 4) are parallel.

We find the slope of parallel line using two given points

(5, -8) and (2, 4)

Slope formula is

$slope = \frac{y_2-y_1}{x_2-x_1}$

$slope = \frac{4-(-8)}{2-5}$

$slope = \frac{12)}{-3}=-4$

so slope = -4

Slope of any two parallel lines are always equal

Lets find the slope of the equation 13y + kx = 4

Subtract kx on both sides

13 y = -kx + 4

Divide both sides by 13

$y= \frac{-kx}{13} + \frac{4}{13}$

Now slope = -k/13

We know slope of parallel lines are same

So the slope of 13y + kx = 4 is also -4

Hence we equation the slope and find out k

$\frac{-k}{13}=-4$

Multiply by 13 on both sides and divide by -1

k = 52

the value of k = 52

4 0

3 years ago

Read 2 more answers

A random sample of size 100 was taken from a population. A 94% confidence interval to estimate the mean of the population was co

Firlakuza [10]

Answer:

Step-by-step explanation:

1) The z value was determined using a normal distribution table. From the normal distribution table, the corresponding z value for a 94% confidence interval is 1.88

The correct option is D

2) if 70% of all internet users experience e-mail fraud. It means that probability of success, p

p = 70/100 = 0.7

q = 1 - p = 1 - 0.7 = 0.3

n = number of selected users = 50

Mean, u = np = 50×0.7 = 35

Standard deviation, u = √npq = √50×0.7×0.3 = 3.24

x = number of internet users

The formula for normal distribution is expressed as

z = (x - u)/s

We want to determine the probability that no more than 25 were victims of e-mail fraud. It is expressed as

P(x lesser than or equal to 25)

The z value will be

z = (25- 35)/3.24 = - 10/3.24 = -3.09

Looking at the normal distribution table, the corresponding z score is 0.001

P(x lesser than or equal to 25) = 0.001

7 0

4 years ago