Can someone help me pleaseeeeeeeeeee

Bones Brothers & Associates prepare individual tax returns. Over prior years, Bones Brothers have maintained careful records

madreJ [45]

Answer:

For this case we have the following info related to the time to prepare a return

$\mu =90 , \sigma =14$

And we select a sample size =49>30 and we are interested in determine the standard deviation for the sample mean. From the central limit theorem we know that the distribution for the sample mean $\bar X$ is given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

And the standard deviation would be:

$\sigma_{\bar X} =\frac{14}{\sqrt{49}}= 2$

And the best answer would be

b. 2 minutes

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".

Solution to the problem

For this case we have the following info related to the time to prepare a return

$\mu =90 , \sigma =14$

And we select a sample size =49>30 and we are interested in determine the standard deviation for the sample mean. From the central limit theorem we know that the distribution for the sample mean $\bar X$ is given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

And the standard deviation would be:

$\sigma_{\bar X} =\frac{14}{\sqrt{49}}= 2$

And the best answer would be

b. 2 minutes

3 0

2 years ago

The time it takes a student to walk from the dorm to the chemistry lab follows roughly a Normaldistribution with a mean of 20 mi

creativ13 [48]

Answer:

95.15%

Step-by-step explanation:

We have that the mean (m) is equal to 20, the standard deviation (sd) 3

They ask us for P (x <25)

For this, the first thing is to calculate z, which is given by the following equation:

z = (x - m) / sd

We have all these values, replacing we have:

z = (25 - 20) / (3)

z = 1.66

With the normal distribution table (attached), we have that at that value, the probability is:

P (z <1.66) = 0.9515

Which means that the probability that it arrives before 25 minutes is 95.15%

6 0

3 years ago

15% of 90 hours<br> 15% of 90 hours

Blizzard [7]

Answer:

15 percent of 90 hours = 13.5 hours

What is 15% of 90?

Y is 15% of 90

Equation: Y = P% * X

Solving our equation for Y

Y = P% * X

Y = 15% * 90

Converting percent to decimal:

p = 15%/100 = 0.15

Y = 0.15 * 90

Y = 13.5

4 0

2 years ago

Read 2 more answers

Help me help me help me

Vinil7 [7]

Answer:

40 dollars the answer is 40!!!

6 0

2 years ago

-6(x-3)+4x simplify the expression

kobusy [5.1K]

Answer: -2x+18

Hope this will help :)

3 0

2 years ago

Read 2 more answers