Solve this for me please.

100 blue marbles to 60 red marbles=

Aloiza [94]

So the ratio is 100:60 and that simplified is 5:3. for every 5 blue there is 3 red

4 0

3 years ago

Read 2 more answers

Evaluate |x + y|, for x = 8 and y = -15. A. 7 B. -7 C. 23 D. -23

Ahat [919]

It's A because 8-15 is -7 but the absolute value parenthesis make it positive 7.

6 0

4 years ago

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It is claimed that automobiles are driven on average more than 20,000 kilometers per year. To test this claim, 100 randomly sele

kow [346]

Answer:

$t=\frac{23500-20000}{\frac{3900}{\sqrt{100}}}=8.974$

$p_v =P(t_{99}>8.974)=9.43x10^{-15}$

If we compare the p value and the significance level given for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we to reject the null hypothesis, and the actual mean is significantly higher than 20000.

Step-by-step explanation:

1) Data given and notation

$\bar X=23500$ represent the sample mean

$s=3900$ represent the sample standard deviation

$n=100$ sample size

$\mu_o =2000$ represent the value that we want to test

$\alpha$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

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

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to determine if the true mean is higher than 20000, the system of hypothesis would be:

Null hypothesis: $\mu \leq 2000$

Alternative hypothesis: $\mu > 2000$

We don't know the population deviation, so for this case is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{23500-20000}{\frac{3900}{\sqrt{100}}}=8.974$

Calculate the P-value

First we need to calculate the degrees of freedom given by:

$df=n-1=100-1=99$

Since is a one-side upper test the p value would be:

$p_v =P(t_{99}>8.974)=9.43x10^{-15}$

Conclusion

If we compare the p value and the significance level given for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we to reject the null hypothesis, and the actual mean is significantly higher than 20000.

8 0

3 years ago

Isabella has twice as much money invested at 4% as she has invested at 3%, and she has $500 more invested at 5% than she has at

adell [148]

Invested at 3% = x
invested at 4% = 2x
invested at 5% = x+500

0.03x + 0.04(2x) + 0.05(x+500) = 2025
0.03x + 0.08x +0.05x +25 = 2025
0.16x = 2000
x= 12,500
4% = 2x = 12,500 * 2 = $25,000

3 0

3 years ago

Zack has an old car. He wants to sell it for 60% off the current price. The

Lelechka [254]

Answer:

300 dollars

Step-by-step explanation:

60% of 500

(60/100) * 500 = 300

4 0

3 years ago