What's -20 times -10 times -1 times 0

How to find cos2theta

SSSSS [86.1K]

You can use the sum and difference identities which for cosine is cos(a+b)= cosacosb-sinasinb

5 0

3 years ago

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Solve the equation

Klio2033 [76]

Answer:

x = 25

Step-by-step explanation:

.20x + .68(120 - x) = .54(120) (Distribute .68 to 120 and -x)

.20x + 81.6 - .68x = .54(120) (multiply .54 and 120)

.20x + 81.6 - .68x = 69.6 ( add .20x and -.68x)

-.48x + 81.6 = 69.6 ( subtract 81.6 on each side)

-.48x = -12 (divide -12 by -.48)

x = 25

4 0

4 years ago

2% of 0.00003 equals?

kakasveta [241]

Answer:

6e-7? i used a percentage calculator and this is what it gave me so im not entirely sure

Step-by-step explanation:

3 0

3 years ago

According to an article in Newsweek, the natural ratio of girls to boys is 100:105. In China, the birth ratio is 100:114 (46.7%

mojhsa [17]

Answer:

$z=\frac{0.42 -0.467}{\sqrt{\frac{0.467(1-0.467)}{150}}}=-1.154$

$p_v =2*P(z$

So the p value obtained was a very high value and using the significance level given $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the proportion of girls born is not significantly different from 0.467

Step-by-step explanation:

Data given and notation

n=150 represent the random sample taken

X=63 represent the number of girls born

$\hat p=\frac{63}{150}=0.42$ estimated proportion of girls born

$p_o=0.467$ is the value that we want to test

$\alpha=0.05$ represent the significance level

Confidence=95% or 0.95

z would represent the statistic (variable of interest)

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

Concepts and formulas to use

We need to conduct a hypothesis in order to test the claim that the true proportion if girls is 0.467.:

Null hypothesis: $p=0.467$

Alternative hypothesis: $p \neq 0.467$

When we conduct a proportion test we need to use the z statistic, 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 $p_o$ .

Calculate the statistic

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

$z=\frac{0.42 -0.467}{\sqrt{\frac{0.467(1-0.467)}{150}}}=-1.154$

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 $\alpha=0.05$ . The next step would be calculate the p value for this test.

Since is a bilateral test the p value would be:

$p_v =2*P(z$

So the p value obtained was a very high value and using the significance level given $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the proportion of girls born is not significantly different from 0.467

3 0

3 years ago

Sophie has $4.20 worth of dimes and quarters. She has twice as many quarters as

ikadub [295]

Answer:

Step-by-step explanation:

7 0

3 years ago

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