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Svetradugi [14.3K]

3 years ago

6

An experimental psychologist is interested in whether the color of an animal's surroundings affects learning rate. He tests 16 r

ats in a box with colorful wallpaper. The average rat (of this strain) can learn to run this type of maze in a box without any special coloring in an average of 25 trials, with a variance of 64, and a normal distribution. The mean number of trials to learn the maze, for the rats tested with the colorful wallpaper, is 11.What is the μM ?• A. 8• B. 11• C. 25• D. 64

1 answer:

Olin [163]3 years ago

8 0

Answer: C. 25

Step-by-step explanation:

Given : The average rat (of this strain) can learn to run this type of maze in a box without any special coloring : $\mu=25$

The mean number of trials to learn the maze, for the rats tested with the colorful wallpaper= $M= 11$

We know that the sampling distribution D is given by :-

$\mu_D=\mu$

Similarly the mean of the distribution M in the given situation is given by :_

$\mu_M=\mu=25$

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Vertical shift up then down

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3 years ago

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Find all solutions of the given system of equations (If the system is infinite many solution, express your answer in terms of x)

lisov135 [29]

Answer:

(a) The system of the equations $\left \{ {2x-3y\:=3} \atop {4x-6y\:=3}} \right.$ has no solution.

(b) The system of the equations $\left \{ {4x-6y\:=10} \atop {16x-24y\:=40}} \right.$ has many solutions $y=\frac{2x}{3}-\frac{5}{3}$

Step-by-step explanation:

(a) To find the solutions of the following system of equations $\left \{ {2x-3y\:=3} \atop {4x-6y\:=3}} \right.$ you must:

Multiply $2x-3y=3$ by 2:

$\begin{bmatrix}4x-6y=6\\ 4x-6y=3\end{bmatrix}$

Subtract the equations

$4x-6y=3\\-\\4x-6y=6\\------\\0=-3$

0 = -3 is false, therefore the system of the equations has no solution.

(b) To find the solutions of the system $\left \{ {4x-6y\:=10} \atop {16x-24y\:=40}} \right.$ you must:

Isolate x for $4x-6y=10$

$x=\frac{5+3y}{2}$

Substitute $x=\frac{5+3y}{2}$ into the second equation

$16\cdot \frac{5+3y}{2}-24y=40\\8\left(3y+5\right)-24y=40\\24y+40-24y=40\\40=40$

The system has many solutions.

Isolate y for $4x-6y=10$

$y=\frac{2x}{3}-\frac{5}{3}$

3 0

3 years ago

What is the factorization of the polynomial below?<br> 5x2 - 35x + 60

natita [175]

Answer:

$5(x-3)(x-4)$

Step-by-step explanation:

$5x^2-35x+60$

Start by factoring out a 5:

$5(x^2-7x+12)$

We need to find two integers that have a product of 12, and a sum of -7:

(-3)(-4)=12

-3-4=-7

We can split -7x into -3x and -4x

$5(x^2-3x-4x+12)$

Factor each half separately:

$5[x(x-3)-4(x-3)]$

Since x and -4 are both being multiplied by x-3, we can combine them:

$5(x-3)(x-4)$

7 0

2 years ago

What is the equation of the line perpendicular to y=2x+3.14 going through the points (2,4)?

inessss [21]

Answer:

$x+2y-10=0$

Step-by-step explanation:

Consider an equation: $y=mx+c$

Here, m is the slope of the line and c is the y-intercept.

Given equation is $y=2x+3.14$

Here, slope is $m=2$

As product of slopes of two perpendicular lines is equal to $-1$ , slope of the required line is $m_1=\frac{-1}{m}=\frac{-1}{2}$ .

Let $(x_1,y_1)=(2,4)$

Equation of the required line is $y-y_1=m_1(x-x_1)$

$y-4=\frac{-1}{2}(x-2)\\2(y-4)=-1(x-2)\\2y-8=-x+2\\x+2y-8-2=0\\x+2y-10=0$

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3 years ago

Based on historical data, your manager believes that 40% of the company's orders come from first-time customers. A random sample

Vedmedyk [2.9K]

Answer:

$P(0.26 \leq p \leq 0.43)=0.7204-0.0032=0.7172$

Step-by-step explanation:

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 Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

The population proportion have the following distribution

$p \sim N(p=0.4,\sqrt{\frac{p(1-p)}{n}}=\sqrt{\frac{0.4(1-0.4)}{91}}=0.0514)$

And we can solve the problem using the z score on this case given by:

$z=\frac{p_o -p}{\sqrt{\frac{p(1-p)}{n}}}$

We are interested on this probability:

$P(0.26 \leq p \leq 0.43)$

And we can use the z score formula, and we got this:

$P(\frac{0.26 -0.4}{\sqrt{\frac{0.4(1-0.4)}{91}}} \leq Z \leq \frac{0.43 -0.4}{\sqrt{\frac{0.4(1-0.4)}{91}}})$

$P(-2.726 \leq Z \leq 0.584)$

And we can find this probability like this:

$P(-2.726 \leq Z \leq 0.584)=P(Z$

7 0

3 years ago