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3 years ago

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Each test contains 20 questions. In average, it takes a person to take each test 40 minutes. If I was to get stuck in one out of

5 questions for an additional 2 minutes. How long will it take me to complete 3 of the tests?

1 answer:

kondor19780726 [428]3 years ago

4 0

I think the answer is 144 minutes

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The Highway Safety Department wants to study the driving habits of individuals. A sample of 40 cars traveling on a particular st

Ipatiy [6.2K]

Answer:

We need a sample size of at least 101

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.99}{2} = 0.005$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.005 = 0.995$ , so $z = 2.575$

Now, find the margin of error M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

What sample size is needed to estimate the true average speed to within 2 mph at 99% confidence?

We need a sample of at least n.

n is found when M = 2. So

$M = z*\frac{\sigma}{\sqrt{n}}$

$2 = 2.575*\frac{7.8}{\sqrt{n}}$

$2\sqrt{n} = 2.575*7.8$

$\sqrt{n} = \frac{2.575*7.8}{2}$

$(\sqrt{n})^{2} = (\frac{2.575*7.8}{2})^{2}$

$n = 100.85$

Rounding up

We need a sample size of at least 101

8 0

3 years ago

Read 2 more answers

A customer buys a different book that has an original selling price of $38. The book is discounted 25%. The customer must pay a

krok68 [10]

$38.00 x 0.25= $9.50
$38.00 - $9.50= $28.75
$28.75 x 0.06= $1.725
$28.75 + $1.73= $30.48

5 0

3 years ago

Read 2 more answers

If the null space of A4×5 is exactly a two-dimensional plane, answer the following:

Hatshy [7]

Answer:

I.

A is a 4 x 5 matrix => A: U -> V, dim U = 5, dim V = 4

Null space is exactly two dimensional plane

dim null (A) = 2

II.

Rank A = dim U - dim Null A = 5 - 2 = 3

III.

Number of linearly Independent columns of A is the rank of A = 3

IV.

Yes, The system Ax = b has no solution sometimes as range of A \neq V

V.

Yes,Sometimes Ax = b has a unique solution

VI.

Yes, sometimes Ax = b has infinitely many solutions

8 0

3 years ago

PLEASE ANSWER + BRAINLIEST!!

Firdavs [7]

The correct answer is B. (-1, 3)

Hope this helps :)

6 0

3 years ago

Multiply the following numbers. Reduce the answer to lowest terms. 3 1/4 · 1 1/3

shepuryov [24]

Answer:

I think the answer is 3 1/12

Forgive me if I am wrong though

Step-by-step explanation:

7 0

3 years ago