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2 years ago

Shiloh is doing a survey to find the time her classmates spend at the beach. She asks the following question:

1 answer:

7 0

You would expect her to gather everyone’s time being at the beach and to compare them. Also, yes it is a statistical question because they are trying to find numerical data( whoever spends the most time at the beach)

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A half-century ago, the mean height of women in a particular country in their 20s was 64.7 inches. Assume that the heights of

Ainat [17]

Answer:

99.5% of all samples of 21 of today's women in their 20's have mean heights of at least 65.86 inches.

Step-by-step explanation:

We are given that a half-century ago, the mean height of women in a particular country in their 20's was 64.7 inches. Assume that the heights of today's women in their 20's are approximately normally distributed with a standard deviation of 2.07 inches.

Also, a samples of 21 of today's women in their 20's have been taken.

Let $\bar X$ = sample mean heights

The z-score probability distribution for sample mean is given by;

Z = $\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\mu$ = population mean height of women = 64.7 inches

$\sigma$ = standard deviation = 2.07 inches

The Z-score measures how many standard deviations the measure is away from the mean. After finding the Z-score, we look at the z-score table and find the p-value (area) 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.

Now, Probability that the sample of 21 of today's women in their 20's have mean heights of at least 65.86 inches is given by = P( $\bar X$ $\geq$ 65.86 inches)

P( $\bar X$ $\geq$ 65.86 inches) = P( $\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n} } }$ $\geq$ $\frac{65.86-64.7}{\frac{2.07}{\sqrt{21} } }$ ) = P(Z $\geq$ -2.57) = P(Z $\leq$ 2.57)

= 0.99492 or 99.5%

The above probability is calculated by looking at the value of x = 2.57 in the z table which has an area of 0.99492.

Therefore, 99.5% of all samples of 21 of today's women in their 20's have mean heights of at least 65.86 inches.

3 0

3 years ago

What is the solution to the system of equations? Use the substitution method.

ludmilkaskok [199]

The answer is A. (3,-1/2)

3 0

2 years ago

Which of these functions has an inverse function? Select all that apply.

Goshia [24]

So we want to know which of the following functions has an inverse function. So an inverse function is a function that "reverses" another function. We need to put y instead of x and x instead of y. So for the first case: y=x is x=y so this function has an inverse function. y=x^2 is x=y^2 so y=sqrt(x). y=x^3 is x=y^3 so y=∛x. y=x^4 so x=y^4, y=4√x or forth root of x. So all of our functions have an inverse function.

3 0

3 years ago

A cube has a lateral area of 676 square feet. What is the side length of the cube?

sp2606 [1]

Answer:

13 ft.

Step-by-step explanation:

Lateral Surface area of a cube is the area of 4 sides, front side, back side, left side face and right side face.

It can be seen seen from the attached figure as well.

Each face in a cube is a square. And each side in the cube is equal.

So, Lateral surface area is nothing but 4 $\times$ area of a square.

And we know that area of a square = $side^{2}$ .

Hence, Lateral surface area = $4 \times side^{2}$

As per question:

$4 \times side^{2}$ = 676

$side^2 = 169 \\\Rightarrow side = 13$

Hence, side length of cube = 13 feet.

7 0

3 years ago

Maggie says that if the expression was 12÷3to the second power, you would divide before simplifying 3 to the second power. Is sh

mezya [45]

Answer:

Maggie is incorrect.

Step-by-step explanation:

PEMDAS tells us the order of operations and the steps of solving a mathematical statement. It states that exponents must be performed before multiplication or division.

P - Parentheses

E - Exponents

M - Multiplication

D - Division

A - Addition

S - Subtraction

Therefore, to solve 12÷3² correctly, 3² needs to be simplified to 9 before dividing.

I hope this helps!

4 0

3 years ago