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Wittaler [7]
3 years ago
7

we choose a sample of size 100 from a population of monthly cable bills having standard deviation $20 If we assume the populatio

n mean bill is $65, what is the probability mean of our sample is greater than $70.
Mathematics
1 answer:
igor_vitrenko [27]3 years ago
8 0

Answer:

0.0062

Step-by-step explanation:

Find the standard error.

σ = 20 / √100

σ = 2

Find the z-score.

z = (x − μ) / σ

z = (70 − 65) / 2

z = 2.5

Find the probability.

P(Z > 2.5) = 1 − 0.9938

P(Z > 2.5) = 0.0062

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Answer:

x = 5 , y = 15

Step-by-step explanation:

You can solve this using substitution.

Let the quantity of cheese wafers be denoted by x and the quantity of chocolate wafers denoted by y

2x + 1y = 25

x + y = 20

These two equations are the answer to part A, (remember to include the above prompt which says what x and y denote).

For part B I used substitution because it was more applicable to the question then addition or elimination.

ACTUAL WORK

Set 2x + 1y = 25 equal to x

x = 25 - y / 2

Replace x with y in the second equation

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And solve for y

y = 15

Since we know what y is we can replace y in the second equation and find what x is

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Solve for x

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3 years ago
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7 0
3 years ago
4.)star liked to practice her number sense when possible. She
Wittaler [7]

Answer:

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ziro4ka [17]

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Hatshy [7]

Answer:

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