3/4 mate, since a fraction is almost always under 1, (except for improper ones), 3/4 should be 0.75 in decimal form.
<h3>
Answer: C) 81.5%</h3>
This value is approximate.
====================================================
Explanation:
We have a normal distribution with these parameters
- mu = 128 = population mean
- sigma = 30 = population standard deviation
The goal is to find the area under the curve from x = 68 to x = 158, where x is the number of text messages sent per day. So effectively, we want to find P(68 < x < 158).
Let's convert the score x = 68 to its corresponding z score
z = (x-mu)/sigma
z = (68-128)/30
z = -60/30
z = -2
This tells us that the score x = 68 is exactly two standard deviations below the mean mu = 128.
Repeat for x = 158
z = (x-mu)/sigma
z = (158-128)/30
z = 30/30
z = 1
This value is exactly one standard deviation above the mean
-------------------------------------------
The problem of finding P(68 < x < 158) can be rephrased into P(-2 < z < 1)
We do this because we can then use the Empirical rule as shown in the diagram below.
We'll focus on the regions between z = -2 and z = 1. This consists of the blue 13.5% on the left, and the two pink 34% portions. So we will say 13.5% + 34% + 34% = 81.5%
Approximately 81.5% of the the population sends between 68 and 158 text messages per day. This value is approximate because the percentages listed in the Empirical rule below are approximate.
Answer:
x < 4
Step-by-step explanation:
12 – 5x > -8
Subtract 12 from each side
12-12 – 5x > -8-12
-5x> -20
Divide each side by -5, remembering to flip the inequality
-5x/-5 < -20/-5
x < 4
Answer:
B) √229
Step-by-step explanation:
√229 is about 15.13, which is the approximate location of point B.
__
IMO, the dot at point P is a little too far to the right for √229.
The formula to calculate circumference is πd or 2πr. We also know that 2r = d.
So, using these formulas, let's try to figure out the first row of the table.
The diameter is 14.
We know that 2r = d or 2r = 14, therefore r=7. This means the radius is 7.
The circumference is πd or 14π or ≈ 43.96.
Let's move to the second row.
We know that the radius is 21.
2r = d
2(21) = d
d = 42
The diameter is 42.
Therefore, the circumference is 42π or ≈ 131.88
Let's move to the final row.
We know that the radius is 10.5.
2r = d
2(10.5) = d
d=21
Therefore, the diameter is 21 cm.
Circumference = πd = 21π or ≈ 65.94