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Musya8 [376]
1 year ago
11

Two friends race against each other in 100-meter and 800-meter races. Of the 200 races they ran this year, the wins, losses, and

ties are shown below.
100 meter (Event D) 800 meter (Event E)
A won the race (Event A) 30 50
B won the race (Event B)60 25
A and B tied (Event T)10 25
What percentage of all the races are ties? If someone wins the race today, is it more likely for A to win or B to win? How much more likely?
Mathematics
1 answer:
sveta [45]1 year ago
5 0
1. <span>What percentage of all the races are ties?
If</span>The chance for the race become tie is 10% for 100m and 25% for 800m. Assuming that the 200 race is divided equally, then there would be 100 race of 100-m and 100 race of 800-m.
The number of the event of ties would be:
(100*10% + 100*25%)/ 200= 35/200= 17.5%

2. If someone wins the race today, is it more likely for A to win or B to win? How much more likely?The event should be independent because the two events should not influence each other. That means the probability will not change and no one becomes more likely to win the next race.
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A battery factory typically produces 12,000 batteries per day and uses 50 boxes for packing the batteries. If the number of boxe
weqwewe [10]

Answer:

25 more boxes is needed

Step-by-step explanation:

12000 batteries require 50 boxes. Let's find the unit rate.

That is, how many batteries are in each box??

That's 12,000/50!

12,000/50 = 240 batteries per box

Now, to find how many boxes we would need for 18,000 batteries, we will have to divide the total (18000) by 240(number of batteries per box). That is:

18,000/240 = 75 boxes

We would need 75 boxes to pack 18,000 batteries.

We want "how many MORE boxes needed", so we will the excess:

75 - 50 = 25 more boxes is needed

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1 year ago
Explain why there are two sine ratios, two cosine ratios, and two tangent ratios for any right triangle
taurus [48]
Each angle has a sin, cos, and tan associated with it.
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5 0
1 year ago
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It is believed that as many as 23% of adults over 50 never graduated from high school. We wish to see if this percentage is the
JulijaS [17]

Answer:

1)  n=48  

2) n=298

3) n=426

Step-by-step explanation:

Previous concepts

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".  

p represent the real population proportion of interest

\hat p represent the estimated proportion for the sample

n is the sample size required (variable of interest)

z represent the critical value for the margin of error

The population proportion have the following distribution  

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

Part 1

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by \alpha=1-0.90=0.10 and \alpha/2 =0.05. And the critical value would be given by:  

z_{\alpha/2}=-1.64, z_{1-\alpha/2}=1.64  

The margin of error for the proportion interval is given by this formula:  

ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}} (a)  

And on this case we have that ME =\pm 0.1 and we are interested in order to find the value of n, if we solve n from equation (a) we got:  

n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2} (b)

We can assume that the estimated proportion is 0.23 for the 25 to 30 group. And replacing into equation (b) the values from part a we got:  

n=\frac{0.23(1-0.23)}{(\frac{0.1}{1.64})^2}=47.63  

And rounded up we have that n=48  

Part 2

The margin of error on this case changes to 0.04 so if we use the same formula but changing the value for ME we got:

n=\frac{0.23(1-0.23)}{(\frac{0.04}{1.64})^2}=297.7  

And rounded up we have that n=298  

Part 3

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by \alpha=1-0.95=0.05 and \alpha/2 =0.025. And the critical value would be given by:  

z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96  

The margin of error for the proportion interval is given by this formula:  

ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}} (a)  

And on this case we have that ME =\pm 0.04 and we are interested in order to find the value of n, if we solve n from equation (a) we got:  

n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2} (b)

We can assume that the estimated proportion is 0.23 for the 25 to 30 group. And replacing into equation (b) the values from part a we got:  

n=\frac{0.23(1-0.23)}{(\frac{0.04}{1.96})^2}=425.22  

And rounded up we have that n=426  

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Jordan used the distributive property to write an expression that is equivalent to 6c – 48. 6c - 48 is equivalent to 6(c - 48) I
Katyanochek1 [597]
It’s incorrect.

The correct answer is 6(c - 8)
8 0
1 year ago
Read 2 more answers
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