If f (x) = 2 x + 5 and three-halves are inverse functions of each other and f(x)=2x+5, what is f-1(8)?

The scores on a statistics test had a mean of 81 and a standard deviation of 9. One student was absent on the test day and his s

Art [367]

Answer: E) Mean will decrease, standard deviation will decrease

Step-by-step explanation:

Initial mean = 81

Initial standard deviation = 9

New score = 78

Taking a look at the initial mean(averahe) score, which is 81 and the new score to be added to the initial scores, the initial average is greater than the new score. Hence, this will result in a decrease in the new mean score after adding the new score of 78.

Also, taking a look at the standard deviation which is 9, we can conclude that the variability in initial scores from the mean scores is high. However, the new score of 78 and the initial mean are very close, and tend to low variation. Hence, adding the new score will lead to a decrease in variability and hence a decrease in the value of standard deviation.

8 0

2 years ago

Suppose a continuous probability distribution has an average of μ=35 and a standard deviation of σ=16. Draw 100 times at random

yulyashka [42]

Answer:

To use a Normal distribution to approximate the chance the sum total will be between 3000 and 4000 (inclusive), we use the area from a lower bound of 3000 to an upper bound of 4000 under a Normal curve with its center (average) at 3500 and a spread (standard deviation) of 160 . The estimated probability is 99.82%.

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.

For sums, we have that the mean is $\mu*n$ and the standard deviation is $s = \sigma \sqrt{n}$

In this problem, we have that:

$\mu = 100*35 = 3500, \sigma = \sqrt{100}*16 = 160$

This probability is the pvalue of Z when X = 4000 subtracted by the pvalue of Z when X = 3000.

X = 4000

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

By the Central Limit Theorem

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

$Z = \frac{4000 - 3500}{160}$

$Z = 3.13$

$Z = 3.13$ has a pvalue of 0.9991

X = 3000

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

$Z = \frac{3000 - 3500}{160}$

$Z = -3.13$

$Z = -3.13$ has a pvalue of 0.0009

0.9991 - 0.0009 = 0.9982

So the correct answer is:

To use a Normal distribution to approximate the chance the sum total will be between 3000 and 4000 (inclusive), we use the area from a lower bound of 3000 to an upper bound of 4000 under a Normal curve with its center (average) at 3500 and a spread (standard deviation) of 160 . The estimated probability is 99.82%.

5 0

2 years ago

. A cyclist pedals his bike 6.5 km up a mountain road, which has a steady incline. By the time he has reached the top of the mou

Elan Coil [88]

Answer:

9.72°

Step-by-step explanation:

Step one

Given data

let the hypotenuse be the distance the cyclist traveled = 6.5km

and let the opposite be the height of the mountain = 1.1 km

Step two:

<u>Applying SOH CAH TOA</u>

sin ∅= opp/hyp

∅= sin-1 opp/hyp

∅= sin-1 1.1/6.5

∅= sin-1 0.169

∅=9.72°

5 0

1 year ago

Carla packed this box with 1 centimeter cubes what is the volume of the box

shusha [124]

Answer: $60\ cm^3$

Step-by-step explanation:

<h3> The complete exercise is attached.</h3>

You can observe in the picture attached that the box is a rectangular prism.

The volume of a rectangular prism can be found with this formula:

$V=lwh$

Where "l" is the length, "w" is the width and "h" is the height.

You know that the lenght of each side of those cubes is 1 centimeter. Therefore, you can multiply the number of cubes on each side of the box by 1 centimeter in order to find the lenght, the width and the height of the box:

$l=(4)(1\ cm)=4\ cm\\\\w=(3)(1\ cm)=3\ cm\\\\h=(5)(1\ cm)=5\ cm$