MATHEMATICS HIGH SCHOOL

The mean shoe size of the students in a math class is 7.5. Most of the shoe sizes fall within 1 standard deviation, or between a size 6 and a size 9.What is the standard deviation of the shoe size data for the math class?
A.1.5
B.2.7
C.3.0
D.3.8

Answers

Answer 1
Answer: Answer: Option A. 1.5

Mean shoe size of the students in a math class: µ=7.5
Standard deviation: σ
Most of the shoe sizes (x) fall within 1 standard deviation:
µ-1σ<x< µ+1σ

µ-σ<x< µ+σ

or between a size 6 and a size 9:
6<x<9

Comparing µ-σ<x< µ+σ with6<x<9:
µ-σ=6 or µ+σ=9

Replacing µ=7.5 above:
7.5-σ=6 or 7.5+σ=9

Solving for σ:
7.5-σ-7.5=6-7.5 or 7.5+σ-7.5=9-7.5
-σ=-1.5 or σ=1.5
σ=1.5 or σ=1.5
Then σ=1.5
Answer 2
Answer: The formula of standard deviation is 
SD = square root of (variance)

Variance is the average of the squared differences from the Mean.
Variance = (6-7.5)^2 + (9-7.5)^2 / 2
Variance = 2.25

SD = square root (2.25)
SD = 1.5

The correct answer is A. 1.5

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Simplify the expression fraction with numerator of the square root of negative one and denominator of the quantity three plus eight times i minus the quantity two plus five times i.fraction with numerator x-3 plus i and denominator 10
fraction with numerator negative 3 plus i and denominator 10
fraction with numerator 3 minus i and denominator 10
fraction with numerator negative 3 minus i and denominator 10

Answers

The simplified expression is: \mathbf{(i+13)/(170)}

The fraction is given as:

\mathbf{(√(-1))/(3 +8i -2 + 5i)}

Collect like terms

\mathbf{(√(-1))/(3 +8i -2 + 5i) = (√(-1))/(3 -2+8i + 5i)}

\mathbf{(√(-1))/(3 +8i -2 + 5i) = (√(-1))/(1+13i)}

In complex numbers, we have:

\mathbf{i =√(-1)}

So, we have:

\mathbf{(√(-1))/(3 +8i -2 + 5i) = (i)/(1+13i)}

Rationalize

\mathbf{(√(-1))/(3 +8i -2 + 5i) = (i)/(1+13i) * (1-13i)/(1-13i)}

\mathbf{(√(-1))/(3 +8i -2 + 5i) = (i(1-13i))/(1^2-(13i)^2)}

\mathbf{(√(-1))/(3 +8i -2 + 5i) = (i-13(-1))/(1-169(-1))}

\mathbf{(√(-1))/(3 +8i -2 + 5i) = (i+13)/(170)}

Hence, the simplified expression is: \mathbf{(i+13)/(170)}

Read more about expressions at:

brainly.com/question/403991
The right answer for the question that is being asked and shown above is that: "fraction with numerator negative 3 minus i and denominator 10." This is the simplified expression fraction with numerator of the square root of negative one and denominator of the quantity three plus eight times i minus the quantity two plus five times i.

Mindy makes $3400 a month. She spends 30% of her money on her house payment, 20% on food costs, 25% on her car note, 10% on other bills, and the rest is spending money. How much spending money should she have?

Answers