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Eduardwww [97]
2 years ago
6

A nationwide survey of 100 boys and 50 girls in the first grade found that the daily average number of boys who are absent from

school is 15, with a standard deviation of 7. For girls, the average number of absentees is 10, with a standard deviation of 6. The standard deviation of the difference is
Mathematics
2 answers:
dusya [7]2 years ago
6 0
Te difference of 2 standard deviation of a population n1 & n2 is given by the formula:
sigma (difference)=√(sigma1/n1 + sigma2/n2), Plug:

sigma(d)= √(49/100 + 36/50)

Sigma(d=difference) =1.1

Gala2k [10]2 years ago
5 0

Find the mean difference (male absences minus female absences) in the population.

μd = μ1 - μ2 = 15 - 10 = 5

Find the standard deviation of the difference.

σd = sqrt( σ12 / n1 + σ22 / n2 )

σd = sqrt(72/100 + 62/50) = sqrt(49/100 + 36/50) = sqrt(0.49 + .72) = sqrt(1.21) = 1.1

Find the z-score that produced when boys have three more days of absences than girls. When boys have three more days of absences, the number of male absences minus female absences is three. And the associated z-score is

z = (x - μ)/σ = (3 - 5)/1.1 = -2/1.1 = -1.818

Find the probability. This problem requires us to find the probability that the average number of absences in the boy sample minus the average number of absences in the girl sample is less than 3. To find this probability, we enter the z-score (-1.818) into Stat Trek's Normal Distribution Calculator. We find that the probability of a z-score being -1.818 or less is about 0.035


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Hiro painted his room at a rate of 8 square meters per hour. After 3 hours of painting, he had 28 square meters left to paint. L
lesya692 [45]

Answer: A(t)=-8t+52

Step-by-step explanation:

<h3> The missing question is: "What is the Functions formula A(t)=?"</h3><h2 />

The  equation of the line in Slope-Intercept form is:

y=mx+b

Where "m" is the slope and "b" is the y-intercept.

According to the data given in the exercise, you know that:

- A(t) represents the area to paint the Hiros' romm as a function of time.

- The rate he painted the room was 8 square meters per hour.

- The area left to paint after 3 hours was 28 m².

Therefore, based on this, you can idenfity that:

1. The slope of the line is:

m=-8

2. One of the point on the line is:

(3,28)

So you must substitute the slope and the coordinates of that point into y=mx+b and then solve for "b" in order to find its value:

28=-8(3)+b\\\\28+24=b\\\\b=52

Therefore, you can determine that the function A(t) is:

A(t)=-8t+52

4 0
1 year ago
Factories 24x^2-41x+12
andriy [413]

Answer:

(3x - 4)(8x - 3)

Step-by-step explanation:

Consider the factors of the product of the coefficient of the x² term and the constant term which sum to give the coefficient of the x- term.

product = 24 × 12 and sum = - 41

The required factors are - 32 and - 9

Use these factors to split the x- term

24x² - 32x - 9x + 12 ( factor the first/second and third/fourth terms )

= 8x(3x - 4) - 3(3x - 4) ← factor out (3x - 4) from each term

= (3x - 4)(8x - 3) ← in factored form

5 0
2 years ago
Jonathons piggy bank contains 20 nickels 30 quarters and 50 one dollar coins. He picks 20 coins from the bank at random
fredd [130]

Answer:

All in all, Jonathan's piggy bank contains 100 coins. Among these coins, only 50 are one-dollar coins. Therefore, the theoretical probability of picking one-dollar coin from the piggy bank is equal to 50/100 or 1/2.  

Similarly, from the experiment, 20 coins were picked and among these there are 12 one-dollar coins. The answer to the second question is therefore 12/20 or 3/5.

Step-by-step explanation:

4 0
1 year ago
Q3. a cyclist bikes x distance at 10 miles per hour and returns over the same path at 8 miles per hour. what is the cyclist's av
Sladkaya [172]
If he bikes for 10 miles per hour and 8 miles per hour for the same distance x miles, he went 10 miles per hour for x/10 hours, as Distance = Rate*Time and on the way back he would go for x/8 hours. So then he went 2x distance, in x/8 + x/10 hours. Since x/8 + x/10 = 10x/80 + 8x/80 = 18x/80 = 9x/40, he went 2x miles in 9x/40 hours. this can be converted into a rate with the above equation Distance = Rate*Time, so 2x=(9x/40) * Rate, thus we divide by 9x/40 on both sides to get 80x/9x = Rate, the x cancels out, and we get 80/9 Miles per hour.
4 0
2 years ago
What is 63.4 divided by 20
Zanzabum
317 is the answer you are looking for.
6 0
1 year ago
Read 2 more answers
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