2.

Alborosie

6.75%
1 penny = 50% chance of tail
50% x 50% x 50% x 50%= 6.75%

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

Y=x²-6x+8 what is y when x is 0?

jarptica [38.1K]

Answer:

The value of y is 8.

Step-by-step explanation:

In order to find the value of y, you have to put in x = 0 into the equation :

$y = {x}^{2} - 6x + 8$

Let x = 0,

$y = {0}^{2} - 6(0) + 8$

$y = 8$

6 0

3 years ago

In a national survey of 1987 adults, 1570 responded that lack of respect and courtesy in American society is a serious problem,

Alik [6]

<h2>Answer with explanation:</h2>

As per given , we have

$H_0: p\leq\dfrac{3}{4}\\\\H_a: p>\dfrac{3}{4}$

Since , alternative hypothesis is right tailed, so the test is a right tailed test.

n= 1987

Proportion of adults believe that rudeness is a worsening problem : $p=\dfrac{1257}{1987}\approx 0.6326$

Test statistic : $z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}$

$z=\dfrac{ 0.6326-0.75}{\sqrt{\dfrac{0.75(1-0.75)}{1987}}}=-12.09$

(since , the normal curve takes values of z from -7 to 7, so we use critical value to draw conclusion.)

The critical value for a significance level of 0.005= 1.645

Since , absolute test statistic value (12.09) is greater than the critical value (1.645), it means there is statistical significance and so we reject the null hypothesis.

3 0

3 years ago

Vanessa deposited money into a bank account that earned 1.25% simple interest each year. After 1/2 year, she had earned $5.00 in

babunello [35]

$800 :P
lolololololollolololol

8 0

3 years ago

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