Answer:
2.5
Step-by-step explanation:
Answer:
the probability that a randomly chosen test-taker will score 142 or lower = 0.8643
Step-by-step explanation:
We are given;
Data point; x = 142
Mean; μ = 153
Standard deviation; σ = 10
So,let's find the z-score using;
z = (x - μ)/σ
z = (142 - 153)/10
z = -1.1
From the z-distribution table attached, the probability is;
P(z < -1.1) = 1 - 0.13567 ≈ 0.8643
Considering the given histogram, the mean of the data-set is closest to:
B. 5.
<h3>What is an histogram?</h3>
An histogram is a graph that shows the number of times each element of x was observed.
<h3>What is the mean?</h3>
The mean of a data-set is given by the <u>sum of all observations in the data-set divided by the number of observations</u>.
Hence, considering the histogram, the mean is given by:
M = (1x1 + 2x2 + 3x3 + 4x1 + 5x1 + 6x2 + 7x3 + 8x1 + 9x1)/(1 + 2 + 3 + 1 + 1 + 2 + 3 + 1 + 1) = 4.87.
Which is closest to 5, hence option B is correct.
More can be learned about histograms at brainly.com/question/26622630
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Answer:
1/4 is to 3/12
Step-by-step explanation:
1 * 3 = 3
4 * 3 = 12
You can start by subtracting different equations from each other.
3x + 2y + 3z = 1
subtract
3x + 2y + z = 7
2z = -6
divide by 2
z = -3
add the following two expressions together:
3x + 2y + z = 7
3x + 2y + 3z =1
6x + 4y + 4z = 8
subtract the following two expressions:
6x + 4y + 4z = 8
5x + 5y + 4z = 3
x - y = 5
^multiply the whole equation above by 3
3x - 3y = 15
subtract the following two expressions:
3x - 3y = 15
3x + 2y = 10
-5y = 5
divide each side by -5
y=-1
take the following expression from earlier:
x - y = 5
substitute y value into above equation
x - - 1 = 5
2 negatives make a positive
x + 1 = 5
subtract 1 from each side
x = 4
Therefore x = 4, y = -1, z = -3
I checked these with all 3 equations and they worked :)
(it's quite complicated, comment if you don't understand anything) :)