Please help.

Sociologists want to test whether the number of homeless people in a particular urban area is increasing. In 2010, the average n

kvv77 [185]

Answer:

single sample z test

Step-by-step explanation: The correct statistics test is the single sample A test.

A one-sample z-test is used to test whether a population parameter is remarkably different from some hypothesized value. Each makes a statement about how the true population mean μ is related to some hypothesized value M. It is used to test whether the mean of a population is greater than, less than, or not equal to a specific value.

5 0

3 years ago

Which method is not used to find the solution of a system of linear equations. guess and checkA. graphingB. substitutionC. matri

ra1l [238]

Answer:

guess and check

Step-by-step explanation:

Linear equation systems usually have two or more variables to find.

The values for these variables can be found by different methods, some of them are indeed graphing, substitution and with matrices.

So these are correct options that are used to solve linear systems of equations.

On the other hand, the guess and check method is not used to find the solution of these systems, since the more variables the system has the more difficult it is to guess the answer, the graphic and mathematical methods are more effective and reliable.

6 0

3 years ago

Lengths of full-term babies in the US are Normally distributed with a mean length of 20.5 inches and a standard deviation of 0.9

mash [69]

Answer:

66.48% of full-term babies are between 19 and 21 inches long at birth

Step-by-step explanation:

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.

Mean length of 20.5 inches and a standard deviation of 0.90 inches.

This means that $\mu = 20.5, \sigma = 0.9$

What percentage of full-term babies are between 19 and 21 inches long at birth?

The proportion is the p-value of Z when X = 21 subtracted by the p-value of Z when X = 19. Then

X = 21

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

$Z = \frac{21 - 20.5}{0.9}$

$Z = 0.56$

$Z = 0.56$ has a p-value of 0.7123

X = 19

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

$Z = \frac{19 - 20.5}{0.9}$

$Z = -1.67$

$Z = -1.67$ has a p-value of 0.0475

0.7123 - 0.0475 = 0.6648

0.6648*100% = 66.48%

66.48% of full-term babies are between 19 and 21 inches long at birth

5 0

2 years ago

-2(x - 5) = -14 PLEASEEEEE HELPPPPPP

juin [17]

Okay so you need to start off by using the distributive property, meaning you are going to multiply -2 by both items within the parentheses. this gives you -2x + 10 = -14. from here you want to isolate x, so you’ll subtract both sides by 10 to move it to the other side. this gives you -2x=-24. then you’ll divide both sides by -2 to completely isolate x. this gives you x=12. does that make sense?

8 0

3 years ago

Consider the equation below. (If an answer does not exist, enter DNE.) f(x) = x4 ln(x) (a) Find the interval on which f is incre

Ainat [17]

Answer: (a) Interval where f is increasing: (0.78,+∞);

Interval where f is decreasing: (0,0.78);

(b) Local minimum: (0.78, - 0.09)

(c) Inflection point: (0.56,-0.06)

Interval concave up: (0.56,+∞)

Interval concave down: (0,0.56)

Step-by-step explanation:

(a) To determine the interval where function f is increasing or decreasing, first derive the function:

f'(x) = $\frac{d}{dx}$ [ $x^{4}ln(x)$ ]

Using the product rule of derivative, which is: [u(x).v(x)]' = u'(x)v(x) + u(x).v'(x),

you have:

f'(x) = $4x^{3}ln(x) + x_{4}.\frac{1}{x}$

f'(x) = $4x^{3}ln(x) + x^{3}$

f'(x) = $x^{3}[4ln(x) + 1]$

Now, find the critical points: f'(x) = 0

$x^{3}[4ln(x) + 1]$ = 0

$x^{3} = 0$

x = 0

and

$4ln(x) + 1 = 0$

$ln(x) = \frac{-1}{4}$

x = $e^{\frac{-1}{4} }$

x = 0.78

To determine the interval where f(x) is positive (increasing) or negative (decreasing), evaluate the function at each interval:

interval x-value f'(x) result

0<x<0.78 0.5 f'(0.5) = -0.22 decreasing

x>0.78 1 f'(1) = 1 increasing

With the table, it can be concluded that in the interval (0,0.78) the function is decreasing while in the interval (0.78, +∞), f is increasing.

Note: As it is a natural logarithm function, there are no negative x-values.

(b) A extremum point (maximum or minimum) is found where f is defined and f' changes signs. In this case:

Between 0 and 0.78, the function decreases and at point and it is defined at point 0.78;
After 0.78, it increase (has a change of sign) and f is also defined;

Then, x=0.78 is a point of minimum and its y-value is:

f(x) = $x^{4}ln(x)$

f(0.78) = $0.78^{4}ln(0.78)$