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3 years ago

12

Plz help plz plz asap

1 answer:

dexar [7]3 years ago

4 0

Answer:

sorry I dotn think I'm that good...

Step-by-step explanation:

[sorry for the waist of time....]

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Which property is illustrated by the equation 3 (m n) = (3 m) n?

Sav [38]

Associative property

8 0

3 years ago

Read 2 more answers

A sample size 25 is picked up at random from a population which is normally

Margarita [4]

Answer:

a) P(X < 99) = 0.2033.

b) P(98 < X < 100) = 0.4525

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 normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score 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 p-value, 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.

Mean of 100 and variance of 36.

This means that $\mu = 100, \sigma = \sqrt{36} = 6$

Sample of 25:

This means that $n = 25, s = \frac{6}{\sqrt{25}} = 1.2$

(a) P(X<99)

This is the pvalue of Z when X = 99. So

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

By the Central Limit Theorem

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

$Z = \frac{99 - 100}{1.2}$

$Z = -0.83$

$Z = -0.83$ has a pvalue of 0.2033. So

P(X < 99) = 0.2033.

b) P(98 < X < 100)

This is the pvalue of Z when X = 100 subtracted by the pvalue of Z when X = 98. So

X = 100

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

$Z = \frac{100 - 100}{1.2}$

$Z = 0$

$Z = 0$ has a pvalue of 0.5

X = 98

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

$Z = \frac{98 - 100}{1.2}$

$Z = -1.67$

$Z = -1.67$ has a pvalue of 0.0475

0.5 - 0.0475 = 0.4525

So

P(98 < X < 100) = 0.4525

6 0

2 years ago

Rewrite the expression with rational exponents as a radical expression.

Jlenok [28]

Answer:

(cube√7x)^2

see above

(√7x)^3

(7√x)^3

6 0

3 years ago

9.<br><br><br>How many times greater is the 6 in 6,275 than the 6 in 62.75?

joja [24]

Answer:100

Step-by-step explanation:

3 0

2 years ago

The sum of three numbers is 104. The first number is 10 less than the second. The third number is 4 times the second. What are t

AnnyKZ [126]

Answer:

The numbers are 9, 19 and 76.

Step-by-step explanation:

Let's take the second number and make it a variable, like x. Now let's find all the other numbers in terms of x.

The first number in terms of x:

$x - 10$

The second number in terms of x:

$4x$

If we add them all up, these 3 numbers in terms of x must be equal to 104, so:

$x + (x - 10) + (4x) = 104 \\ x + x - 10 + 4x = 104 \\ 6x - 10 = 104 \\ 6x = 114 \\ x = 19$

Now that we know the second number, we can find the other numbers since we already figured out their values in terms of x:

$19 - 10 = 9$

$4 \times 19 = 76$

The first number is 9, second number 19 and the third number 76.

6 0

3 years ago