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3 years ago

Roberto evaluated 3/4 ÷ 4/5 and got an answer of 15/16. which statement is true about his answer?

Mathematics

1 answer:

Murrr4er [49]3 years ago

5 0

Roberto's solution to the division problem is correct, but
there are no true statements on your list of choices.

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A standard weight known to weigh 10 grams. Some suspect bias in weights due to manufacturing process. To assess the accuracy of

notsponge [240]

Answer:

a) The 98% confidence interval for the mean weight is between 10.00409 grams and 10.00471 grams

b) 49 measurements are needed.

Step-by-step explanation:

Question a:

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

$\alpha = \frac{1 - 0.98}{2} = 0.01$

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

That is z with a pvalue of $1 - 0.01 = 0.99$ , so Z = 2.327.

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.

$M = 2.327\frac{0.0003}{\sqrt{5}} = 0.00031$

The lower end of the interval is the sample mean subtracted by M. So it is 10.0044 - 0.00031 = 10.00409 grams

The upper end of the interval is the sample mean added to M. So it is 10 + 0.00031 = 10.00471 grams

The 98% confidence interval for the mean weight is between 10.00409 grams and 10.00471 grams.

(b) How many measurements must be averaged to get a margin of error of +/- 0.0001 with 98% confidence?

We have to find n for which M = 0.0001. So

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

$0.0001 = 2.327\frac{0.0003}{\sqrt{n}}$

$0.0001\sqrt{n} = 2.327*0.0003$

$\sqrt{n} = \frac{2.327*0.0003}{0.0001}$

$(\sqrt{n})^2 = (\frac{2.327*0.0003}{0.0001})^2$

$n = 48.73$

Rounding up

49 measurements are needed.

7 0

3 years ago

Complete the square to re-write the quadratic function in vertex form: y=x2-x+3

Anna [14]

Answer:

Step-by-step explanation:

hello :

note : the vertex form is :

ax²+bx+c = a(x+(b)/(2a))²- delta/4a² and delta = b²- 4ac

in this exercice you have : a =1 b = -1 and c= 3

continu ..........

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2 years ago

Pls help me i need this to get a 100

rjkz [21]

Answer:

?- _ - _- -_ _- -

3 0

2 years ago

Read 2 more answers

HELP ME PLZ! :3

sveta [45]

Part A:
y=mx+b
621=83(7)+b

Part B:
621=83(7)+b
621=581+b
621-581=b
b=40
Insurance cost is 40$

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2 years ago

Tammy rents an apartment close to her school campus. The amount that she spends on rent is given by the equation r = 355m, where

inna [77]

answer is c because if it's not a and b then the only answers will be c and d and d is the same as the number so it's c

8 0

3 years ago