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Ostrovityanka [42]

2 years ago

14

Nina and Ryan each ran at a constant speed for a 100-meter race. Each runner’s distance fro the same section of the race is disp

layed on the left. Who had a head start, and how big was the head start?

2 answers:

tester [92]2 years ago

6 0

Answer:

Ryan for first box 10 for second

Step-by-step explanation:

sergey [27]2 years ago

5 0

Step-by-step explanation:

Ryan had a head start of 10 meters.

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A log is 16m long, correct to the nearest metre. It has to be cut into fence posts which must be 70cm long, correct to the neare

dmitriy555 [2]

Answer:

25 posts

Step-by-step explanation:

So the number of fence post would be the total length of the log divided by the length of each post. As the log is 16m and is corrected to the nearest metre, it could possibly be 16.499m. As for the post that is 70 cm long and corrected to the nearest 10cm, it may as well be 65 cm (or 0.65m) each post

So the max number of fence point once can possibly cut from the log would be

16.499 / 0.65 = 25 posts

5 0

2 years ago

A batch of 500 machined parts contains 10 that do not conform to customer requirements. Parts are selected successively, without

sveticcg [70]

Question:

For the following exercise, determine the range (possible values) of the random variable. A batch of 500 machined parts contains 10 that do not conform to customer requirements. Parts are selected successively, without replacement, until a nonconforming part is obtained. The random variable is the number of parts selected.

Answer:

Possible values are all integers from 1 to 491.

{1,2,...........491}

Step-by-step explanation:

Given:

Total number of machined parts = 500

Number that do not conform to customers requirements = 10

Number that conforms to customers requirements = 500 - 10 = 490

Since, parts are selected successively, without replacement, until a nonconforming part is obtained, the range of the random variable (number of parts selected) here will be all integers from 1 to 491 ie {1,2,...........,491}.

Here, we have a total of 490 conforming parts, and 10 non conforming parts, there must be a non-conforming part among 491 selections, considering the fact that total number of parts are 500

7 0

2 years ago

Drew earns money washing cars for his neighbors on the weekends. Drew charges a set rate for each car he washes.

statuscvo [17]

Answer:

30

Step-by-step explanation:

5 0

2 years ago

Read 2 more answers

A sample of 1714 cultures from individuals in Florida diagnosed with a strep infection was tested for resistance to the antibiot

Damm [24]

Answer:

a) $p$ represent the real population proportion of people who showed partial or complete resistance to the antibiotic

b) $\hat p=\frac{973}{1714}=0.568$ represent the estimated proportion of people who showed partial or complete resistance to the antibiotic

c) We are confident (95%) that the true proportion of individuals in Florida diagnosed with a strep infection was tested for resistance to the antibiotic penicillin present partial or complete resistance to the antibiotic is between 54.5% to 59.1%.

Step-by-step explanation:

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Part a

Description in words of the parameter p

$p$ represent the real population proportion of people who showed partial or complete resistance to the antibiotic

$\hat p$ represent the estimated proportion of people who showed partial or complete resistance to the antibiotic

n=1714 is the sample size required

$z_{\alpha/2}$ represent the critical value for the margin of error

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

Part b

Numerical estimate for p

In order to estimate a proportion we use this formula:

$\hat p =\frac{X}{n}$ where X represent the number of people with a characteristic and n the total sample size selected.

$\hat p=\frac{973}{1714}=0.568$ represent the estimated proportion of people who showed partial or complete resistance to the antibiotic

Part c

The confidence interval for a proportion is given by this formula

$\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

For the 95% confidence interval the value of $\alpha=1-0.95=0.05$ and $\alpha/2=0.025$ , with that value we can find the quantile required for the interval in the normal standard distribution.

$z_{\alpha/2}=1.96$

And replacing into the confidence interval formula we got:

$0.568 - 1.96 \sqrt{\frac{0.568(1-0.568)}{1714}}=0.545$

$0.568 + 1.96 \sqrt{\frac{0.56(1-0.56)}{1714}}=0.591$

And the 95% confidence interval would be given (0.545;0.591).

We are confident that about 54.5% to 59.1% of individuals in Florida diagnosed with a strep infection was tested for resistance to the antibiotic penicillin present partial or complete resistance to the antibiotic.

5 0

2 years ago

n his pocket, Hamid has $2.95 in dimes and quarters. If there are 16 coins in total, which system represents the number of dimes

N76 [4]

X=dimes y=quarters

0.1x + 0.25y = 2.95
x+y = 16

from the second equation, x = 16 - y and thus 0.1 (16-y) +0.25y = 2.95 ==> y=9. Finally, x + 9 = 16 ==> x=7

7 dimes, 9 quarters

4 0

2 years ago

Read 2 more answers