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tiny-mole [99]
3 years ago
11

Suppose that 200 students are randomly selected from a local college campus to investigate the use of cell phones in classrooms.

When asked if they are allowed to use cell phones in at least one of their classes, 40% of students responded yes. Using these results, with 95% confidence, the margin of error is 0.068. How would the margin of error change if the sample size increased from 200 to 400 students?
Mathematics
1 answer:
serious [3.7K]3 years ago
6 0

Answer:

It would change to 0.04802

Step-by-step explanation:

from this question we have that n became 400

40% of 400

= 160

p* = 160/400

= 0.4

1 - p* =

= 1 - 0.4

= 0.6

at confidence level,

1 - 0.95

= 0.05

alpha/2 = 0.025

z= 1.96

<u>margin of error. E</u>

= 1.96 x √[(0.4 x 0.6)/400]

= 1.96 x 0.0245

= 0.04802

M.E = 0.04802

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$6.48

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Which equation is y = 2x2 – 8x + 9 rewritten in vertex form?
pishuonlain [190]

we have

y=2x^{2} -8x+9


Group terms that contain the same variable, and move the constant to the opposite side of the equation

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3 0
3 years ago
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19. When baking a cake, you have a choice of the following pans:
dimaraw [331]

The answer is

round cake - 82.42 in²

rectangular cake - 114 in²

Round cake:

d = 7 in

r = d/2 = 7 in / 2 = 3.5 in

h = 2 in

The surface are of a cylinder is:

A = 2πr² + 2πrh

The surface are of the round cake (which is actually a cylindrical cake) excluding the bottom is:

A = 2πr² + 2πrh - πr²

A = πr² + 2πrh

A = 3.14 * 3.5² + 2 * 3.14 * 3.5 * 2

= 38.46 + 43.96

= 82.42 in²

Rectangular cake:

w = 6 in

l = 9 in

h = 2 in

The surface are of a rectangle is:

A = 2wl + 2wh + 2lh

The surface are of the rectangular cake excluding the bottom is:

A = 2wl + 2wh + 2lh - wl

A = wl + 2wh + 2lh

A = 6 * 9 + 2 * 6 * 2 + 2 * 9 * 2

= 54 + 24 + 36

= 114 in²

Step-by-step explanation: This answer is not mine but JcAlmighty’s so all credits go to them.

7 0
3 years ago
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Find the diameter of a circle with an area of 12.6 square inches ​
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Answer:

Step-by-step explanation

the answer is 10

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