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mina [271]
3 years ago
9

There are 80 students in the 7th grade. 25% of them were absent yesterday. How many

Mathematics
1 answer:
mariarad [96]3 years ago
7 0
I can show you one way. Since 25x4=100 we can start by dividing 80/4. Which gives you 20.
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The heights of women aged 20 to 29 are approximately Normal with mean 64 inches and standard deviation 2.7 inches. Men the same
masha68 [24]

Answer: The z-scores for a woman 6 feet tall is 2.96 and the z-scores for a a man 5'10" tall is 0.25.

Step-by-step explanation:

Let x and y area the random variable that represents the heights of women and men.

Given : The heights of women aged 20 to 29 are approximately Normal with mean 64 inches and standard deviation 2.7 inches.

i.e. \mu_1 = 64   \sigma_1=2.7

Since , z=\dfrac{x-\mu}{\sigma}

Then, z-score corresponds to  a woman 6 feet tall (i.e. x=72 inches).

[∵  1 foot = 12 inches , 6 feet = 6(12)=72 inches]

z=\dfrac{72-64}{2.7}=2.96296296\approx2.96

Men the same age have mean height 69.3 inches with standard deviation 2.8 inches.

i.e. \mu_2 = 69.3   \sigma_2=2.8

Then, z-score corresponds to a man 5'10" tall (i.e. y =70 inches).

[∵  1 foot = 12 inches , 5 feet 10 inches= 5(12)+10=70 inches]

z=\dfrac{70-69.3}{2.8}=0.25

∴ The z-scores for a woman 6 feet tall is 2.96 and the z-scores for a a man 5'10" tall is 0.25.

6 0
3 years ago
Which ordered pair is a solution of the equation?<br> -4r +7= 2y - 3
Mars2501 [29]

Answer:

y=-8, r= 2. this is your answer

6 0
3 years ago
A college student took 4 courses last semester. His final grades, along with the credits each class is worth, are as follow: A (
NikAS [45]

Answer:

A college student took 4 courses last semester. His final grades, along with the credits each class is worth, are as follow: A (3), B (4), C (2), and D (3). The grading system assigns quality points as follows: A: 4; B: 3; C: 2; D: 1; and F: 0. Find the student’s GPA for this semester. Round your answer to the nearest thousandth.

another way is

This is a weighted average question. You are going to "weight" each course by the number of credits it is worth and then divide by the total number of credits. In other words, you are going to multiply each grade (A=4, B=3) by the number of credits attached to that grade. This will ensure that the courses that have more credits count more in the overall average. Then you are going to divide by the total number of credits to get the overall GPA.

So,

(3*4 + 4*3 + 2 *2 + 3*1)/(3+4+2+3) = GPA

Step-by-step explanation:

bran-list please

6 0
3 years ago
The radius of a cylinder is 3 cm and the height is 6 cm.
Ratling [72]

Answer

Step-by-step explanation:

A=2πrh+2πr2=2·π·3·6+2·π·32≈169.646

5 0
3 years ago
Read 2 more answers
Entertainment Software Association would like to test if the average age of "gamers" (those that routinely play video games) is
lions [1.4K]

Answer:

"30 years or less when, in reality, the average age is more than 30 years"

Step-by-step explanation:

Type I error is produced when conclusion rejects a true null hypothesis.

The null hypothesis is

"The average gamer is more than 30 years old"

(deduced from the wording, not explicitly stated).

Then if the conclusion is "the average gamer is less than or equal to 30 years old" when in reality the average age is more than 30 years, then there is a type I error, since the null hypothesis is rejected.

Answer is D:

"30 years or less when, in reality, the average age is more than 30 years"

8 0
3 years ago
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