What ratio is equivalent to 15/40?

Helllppp ASAPppppppp

Julli [10]

Answer:

For number 5 is n=10

Step-by-step explanation:

7 0

3 years ago

A random sample of the correct choice on 400 multiple-choice questions on a variety of AP exams1 shows that B was the most commo

maks197457 [2]

Answer:

a) Null hypothesis: $p\leq 0.2$

Alternative hypothesis: $p > 0.2$

b) $z=\frac{0.225 -0.2}{\sqrt{\frac{0.2(1-0.2)}{400}}}=1.25$

$p_v =P(Z>1.25)=0.106$

Step-by-step explanation:

1) Data given and notation

n=400 represent the random sample taken

X=90 represent the number of questions with B as the correct answer

$\hat p=\frac{90}{400}=0.225$ estimated proportion of arrests that were not prosecuted

$p_o=0.2$ is the value that we want to test, since we assume that each question present 5 options and just one is correct, 1/5 =0.2 if all five options were equally likely

$\alpha$ represent the significance level

z would represent the statistic (variable of interest)

$p_v$ represent the p value (variable of interest)

2) Concepts and formulas to use

We need to conduct a hypothesis in order to test the claim that the true proportion is higher than 0.2.:

Null hypothesis: $p\leq 0.2$

Alternative hypothesis: $p > 0.2$

When we conduct a proportion test we need to use the z statisitc, and the is given by:

$z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}$ (1)

The One-Sample Proportion Test is used to assess whether a population proportion $\hat p$ is significantly different from a hypothesized value $p_o$ .

3) Calculate the statistic

Since we have all the info requires we can replace in formula (1) like this:

$z=\frac{0.225 -0.2}{\sqrt{\frac{0.2(1-0.2)}{400}}}=1.25$

4) Statistical decision

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.

The significance level provided $\alpha$ . The next step would be calculate the p value for this test.

Since is a right tailed test the p value would be:

$p_v =P(Z>1.25)=0.106$

If we compare the p value obtained and the significance level assumed $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL reject the null hypothesis, and we can said that at 5% of significance the proportion of B correct answers is not significantly higher than 0.2.

8 0

4 years ago

Suppose that 3 balls are chosen without replacement from an urn consisting of 3 white and 7 red balls. Assume moreover that the

zimovet [89]

Answer:

P(X1=1, X2=1) = 1/15

P(X1=1, X2=0) = 7/30

P(X1=0, X2=1) = 7/30

P(X1=0, X2=0) = 7/15

Step-by-step explanation:

Let Xi = 1 if the i-th white ball is selected. In this question the 3 white balls are marked 1,2 and 3.

We need to know the possible combination between X1 and X2 i.e. for the white ball 1 and 2 being chosen in the event.

We also need to note that the event is dependent which that after a ball is being chosen, it will not be put back hence affecting the probability of picking the next ball.

Consider all the possible combination between X1 and X2

a) both being chosen P(X1=1, X2=1)

= (3/10) x (2/9) = 1/15

Note that the first probability is the probability before any ball is being picked. The chances for ball white to be pick is 3/10 (3 white ball from the total 10 balls).

After 1 white ball being selected, that ball is not again out back into the urn making white ball 2 and total ball 9. Hence probability of picking another white ball is 2/9

b) only X1 chosen P(X1=1, X2=0)

= (3/10) x (7/9) = 7/30

After the white ball was picked, the probability of white not being pick again is the same as red being picked. Since there is still 7red balls and a total of 9 balls, the probability is 7/9

c) only X2 chosen P(X1=0, X2=1)

= (7/10) x (3/9) = 7/30

The white is not being picked first, making the probability of picking red is 7/10. Then the probability of white being picked is 3/9

d) both not chosen

P(X1=0, X2=0)

= (7/10) x (6/9) = 7/15

In other word only red being chosen. So the first probability is 7 red out of 10 balls (7/10), and the next red ball being picked next is 6/9

7 0

3 years ago

An item is priced at $13.95. It the sales tax is 8%, what does the item cost inchiding sales tax?

DedPeter [7]

Answer:

The answer is D

Step-by-step explanation:

If you do 8/100×13.95 it will land somewhere that and the price cannot be lower that the original price it must be a little nighter but not too much

4 0

3 years ago

PLS HELP MEE!!

Naily [24]

Answer:

1.75 !

Step-by-step explanation:

0.25 x 7

One orange price is 0.25, so you would multiply that by 7 to get the price of 7 oranges!

I'm not sure how to explain this, but if you write it out, and do the math, and move the decimal point correctly, you will get this answer!

4 0

3 years ago

What ratio is equivalent to 15/40?​

What ratio is equivalent to 15/40?