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Oksi-84 [34.3K]
3 years ago
7

If you bike for 60km at 30km/h and return at 20km/h what is your average speed for the whole trip

Mathematics
1 answer:
EastWind [94]3 years ago
6 0
Your average speed is 24Km/h

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How to solve this task 4×-2+1=3×+5
just olya [345]
4x-2+1=3x+5

Subtract 3x from both sides

x-2+1=5

Same as

x-1=5

Add 1 to both sides

x=6
8 0
3 years ago
Many high school students take the AP tests in different subject areas. In 2007, of the 144,796 students who took the biology ex
Nataly [62]

Answer:

(0.582-0.485) - 1.64 \sqrt{\frac{0.582(1-0.582)}{144796} +\frac{0.485(1-0.485)}{211693}}=0.0942  

(0.582-0.485) + 1.64 \sqrt{\frac{0.582(1-0.582)}{144796} +\frac{0.485(1-0.485)}{211693}}=0.09978  

And the 90% confidence interval would be given (0.0942;0.09978).  

We are confident at 90% that the difference between the two proportions is between 0.0942 \leq p_A -p_B \leq 0.09978

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_A represent the real population proportion female for Biology

\hat p_A =\frac{84199}{144796}=0.582 represent the estimated proportion female for biology

n_A=144796 is the sample size for A

p_B represent the real population proportion female for calculus AB

\hat p_B =\frac{102598}{211693}=0.485 represent the estimated proportion female for Calculus AB

n_B=211693 is the sample size required for B

z 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}})  

The confidence interval for the difference of two proportions would be given by this formula  

(\hat p_A -\hat p_B) \pm z_{\alpha/2} \sqrt{\frac{\hat p_A(1-\hat p_A)}{n_A} +\frac{\hat p_B (1-\hat p_B)}{n_B}}  

For the 90% confidence interval the value of \alpha=1-0.90=0.1 and \alpha/2=0.05, with that value we can find the quantile required for the interval in the normal standard distribution.  

z_{\alpha/2}=1.64  

And replacing into the confidence interval formula we got:  

(0.582-0.485) - 1.64 \sqrt{\frac{0.582(1-0.582)}{144796} +\frac{0.485(1-0.485)}{211693}}=0.0942  

(0.582-0.485) + 1.64 \sqrt{\frac{0.582(1-0.582)}{144796} +\frac{0.485(1-0.485)}{211693}}=0.09978  

And the 90% confidence interval would be given (0.0942;0.09978).  

We are confident at 90% that the difference between the two proportions is between 0.0942 \leq p_A -p_B \leq 0.09978

5 0
3 years ago
The ratio of books to magazines at jess house is 5:3 they are 21 magazines at jess house how many books are there?
TiliK225 [7]
First, 5/3 = 1.6
21 x 1.6 = 34.99999999
But, when I put it in a calculator, the 1.6 was repeated so:
Round 34.99999999 to 35
35 books
6 0
2 years ago
Read 2 more answers
Marc left his house to drive to work. As he heads down his street, his speed increases steadily until he sees the stop sign at t
Anna35 [415]
The third graph is the correct answer :)
7 0
3 years ago
Read 2 more answers
find the sum ofthe angle measure in each regular polygon. Then find the measure of each angle. Show work please I'm so bad at th
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For every side you just add 90 to your equation. so #4 would be 360-125-125-55=(55)
6 0
3 years ago
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