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%
Multiplying by 2 and then adding 10 145*2=290+10=300
300*2=600+10=610
610*2=1220 + 10=1230
x=2 y=10
x+y=12
It is often easiest to use "military time". That is, add 12 to all the afternoon numbers and do the subtraction in the usual way. Of course, 1 hour = 60 minutes, so 10 minutes = 10/60 hour = 1/6 hour.
Mon: 15:10 -8:00 = 7:10 = 7 1/6
Tue: 15:25 -8:05 = 7:20 = 7 1/3
Wed: 14:30 -8:00 = 6:30 = 6 1/2
Thur: 14:45 -7:55 = 7:(-10) = 6:50 = 6 5/6
Fri: 15:38 -7:58 = 8:(-20) = 7:40 = 7 2/3
_____
Some calculators have nice features for working with degrees, minutes, and seconds. In this context, degrees and hours are the same thing. That is, the base-60 arithmetic is the same whether you consider the numbers to be hours or degrees. Similarly, some calculators convert nicely between decimal fractions and mixed numbers. In short, a suitable calculator will almost do this math for you. (You just need to add 12 to all the numbers in the column on the right.)
The correct answer is 2.5×10^2
Hope this helped :)
