Find the midpoint of the line segment joining the points (-1,-2) and (-3,13)

A researcher is going to estimate the average typing speed of students of a college. He selects a random sample of 20 students a

Stella [2.4K]

Answer:

The margin of error of the 90% confidence interval of a student's average typing speed is of 1.933 wpm.

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 20 - 1 = 19

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 19 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.9}{2} = 0.95$ . So we have T = 1.7291

The margin of error is:

$M = T\frac{s}{\sqrt{n}}$

In which s is the standard deviation of the sample and n is the size of the sample. For this question, we have $s = 5, n = 20$ . So

$M = T\frac{s}{\sqrt{n}}$

$M = 1.7291\frac{5}{\sqrt{20}}$

$M = 1.933$

The margin of error of the 90% confidence interval of a student's average typing speed is of 1.933 wpm.

8 0

3 years ago

marty has 1 1/3 jugs of apple juice. he uses 3/4 of the juice to make freeze pops. what fraction amount of a jus doe marty have?

Vedmedyk [2.9K]

Answer:

=2 $\frac{1}{12}$

Step-by-step explanation:

We have to make the fractions equal so we can add them

1 $\frac{1}{3}$ ×4= 1 $\frac{4}{12}$

$\frac{3}{4}$ ×3= $\frac{9}{12}$

1 $\frac{4}{12}$ + $\frac{9}{12}$ =2 $\frac{1}{12}$

5 0

3 years ago

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Oliga [24]

Answer:

Part A)

The height of the water level in the rectangular vessel is 2 centimeters.

Part B)

4000 cubic centimeters or 4 liters of water.

Step-by-step explanation:

We are given a cubical vessel that has side lengths of 10cm. The vessel is completely filled with water.

Therefore, the total volume of water in the cubical vessel is:

$V_{C}=(10)^3=1000\text{ cm}^3$

This volume is poured into a rectangular vessel that has a length of 25cm, breadth of 20cm, and a height of 10cm.

Therefore, if the water level is h centimeters, then the volume of the rectangular vessel is:

$V_R=h(25)(20)=500h\text{ cm}^3$

Since the cubical vessel has 1000 cubic centimeters of water, this means that when we pour the water from the cubical vessel into the rectangular vessel, the volume of the rectangular vessel will also be 1000 cubic centimeters. Hence:

$500h=1000$

Therefore:

$h=2$

So, the height of the water level in the rectangular vessel is 2 centimeters.

To find how how much more water is needed to completely fill the rectangular vessel, we can find the maximum volume of the rectangular vessel and then subtract the volume already in there (1000 cubic centimeters) from the maximum volume.

The maximum value of the rectangular vessel is given by :

$A_{R_M}=20(25)(10)=5000 \text{ cm}^3$

Since we already have 1000 cubic centimeters of water in the vessel, this means that in order to fill the rectangular vessel, we will need an additional:

$(5000-1000)\text{ cm}^3=4000\text{ cm}^3$

Sincer 1000 cubic centimeters is 1 liter, this means that we will need four more liters of water in order to fill the rectangular vessel.

3 0

3 years ago

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In the beginning of the study, a randomly selected group of 121 students scored an average of 252 words per minute on the readin

Alborosie

Answer:

Since the sample size is larger than 30, the cognitive psychologist can assume that the sampling distribution of M will be approximately normal.

Step-by-step explanation:

We use the central limit theorem to solve this question.

The Central Limit Theorem estabilishes that, for a random variable X, with mean $\mu$ and standard deviation $\sigma$ , a sample size larger than 30 can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$

So

Since the sample size is larger than 30, the cognitive psychologist can assume that the sampling distribution of M will be approximately normal.

5 0

3 years ago

Angle MNO is formed by segments MN and NO on the following coordinate grid:

Eva8 [605]

Answer:

I am 90% sure that the answer is M'N'O' is 90*

Step-by-step explanation:

A line segment MN is shown as M = -1,1 and N= -5,4 this makes a diagonal line across the grid. Another line segment NO is shown with O as ordered pair negative 1, 4. Angle MNO is rotated 90 degrees counterclockwise about the origin to form angle M′N′O′. this is where the angles meet, Rotating the shape (or the angles) does not change the degree of the angle of the shape. I am 99% sure that an 90* angle would be formed. but im just in middle school so what do i know?

6 0

3 years ago

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