That the teacher gave you extra credit
Answer:
Step-by-step explanation:
The mean of the gas mileages is 317÷16=19.8125
317 is the sum total of all the figures and 16 is the number of figures in the distribution
Standard deviation is the square root of the variance and the variance is the mean of all squared deviations
The 16 squared deviations are
7.9102(×2) + 3.2852(×2) + 0.6602(×3) + 0.0352(×4) + 1.4102(×3) + 10.1602 + 17.5352 = 56.4382
56.4382÷16 = 3.5274
This is the Variance. The standard deviation is herefore √3.5274 =1.878 ~ 1.88 (to 2 decimal places)
(B) Chebyshev's inequality predicts that 75% of the selection will fall within 2 standard deviations of the mean
2×1.88=3.76
19.8125-3.76 = 16.05
19.8125+3.76= 23.57
The gas mileages are between 16.05 and 23.57
(C) the actual % of SUV models of the sample that fall in the above range is (15/16 × 100) = 93.75%
(D) the empirical rule gives the more accurate prediction
Answer:
the answer is option D
Step-by-step explanation:
if you add the no of students in favour of the survey
32+42+58+64=192
which makes the first option incorrect.
The opinion of tenth and eleventh graders are not identical.
11th and 12th graders gave a favourable response
so options A,B and C are incorrect
The smallest amount of material needed is 54 square centimeters
<h3>How to determine the amount of material needed?</h3>
The given parameters are:
Volume = 36 cubic centimeters
Represent length with x, width with y and height with z.
So, we have
x = 3y
The volume is calculated as:
V = xyz
This gives
V = 3y²z
Substitute 36 for V
3y²z = 36
Divide by 3
y²z = 12
Make z the subject
z = 12/y²
The surface area is:
S = 2(xy + xz + yz)
This gives
S = 2(3y² + 3yz + yz)
Evaluate the like terms
S = 2(3y² + 4yz)
Expand
S = 6y² + 8yz
Substitute z = 12/y²
S = 6y² + 8y * 12/y²
This gives
S = 6y² + 96/y
Differentiate
S' = 12y - 96/y²
Set to 0
12y - 96/y² = 0
Multiply through by y²
12y³ - 96 = 0
Add 96 to both sides
12y³ = 96
Divide by 12
y³ = 8
Take the cube root of both sides
y = 2
Recall that:
x = 3y and z = 12/y²
This gives
x = 3 * 2 = 6
z = 12/2² = 3
Recall that:
S = 2(xy + xz + yz)
So, we have:
S = 2(6 * 2 + 3 * 3 + 2 * 3)
Evaluate
S = 54
Hence, the smallest amount of material needed is 54 square centimeters
Read more about surface areas at:
brainly.com/question/76387
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