Answer:
68%
Step-by-step explanation:
The Standard Deviation Rule = Empirical rule formula states that:
68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ.
95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ.
99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ.
From the question,
Step 1
We have to find the number of Standard deviation from the mean. This is represented as x in the formula
μ = Mean = 61
σ = Standard Deviation = 8
For x = 53
μ - xσ
53 = 61 - 8x
8x = 61 - 53
8x = 8
x = 8/8
x = 1
For x = 69
μ + xσ
69 = 61 + 8x
8x = 69 - 61
8x = 8
x = 8/8
x = 1
This falls within 1 standard deviation of the mean where: 68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ.
Therefore, according to the Standard Deviation Rule, the approximate percentage of daily phone calls numbering between 53 and 69 is 68%
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The height of the triangular pyramid will be equal to H=12 feet.
<h3>What is a triangular pyramid?</h3>
A triangular pyramid is a pyramid having triangular faces the other sides of the pyramid are simliar triangles.
It is given that:-
The Volume of the pyramid=80 cubic meters
The Base area of the pyramid=20 square meters
The height of the pyramid=?
We know that the volume of a pyramid is given as:-
V=(1÷3)x Base area x height
V=(1÷3)x20 x H
H=(80x30)÷20
H=12 feet
Hence the height of the triangular pyramid will be equal to H=12 feet.
To know more about pyramid foliow
brainly.com/question/218706
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Answer: 64 and 81
Step-by-step explanation: I used my brain. :)
