Is 8/5 a rational number?

Find the probability of exactly four successes in five trials of a binomial experiment in which the probability of success is 40

hodyreva [135]

Answer:

p(4 successes) ≈ 7.7%

Step-by-step explanation:

p(k successes in n trials) = C(n,k)·p^k·(1-p)^(n-k)

You have n=5, k=4, p=0.4, so the probability is ...

p(4 successes) = C(5,4)·(0.4)^4·(1 -0.4)^1 = 5·0.4^4·0.6 = 0.0768

p(4 successes) ≈ 7.7%

8 0

3 years ago

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A random sample of 85 sixth-graders in a large city take a course designed to improve scores on a reading comprehension test. Ba

BartSMP [9]

Answer:

$12.6 < \mu < 14.8$

For this case we can find the margin of error like this:

$ME= \frac{14.8-12.6}{2}= 1.1$

Since we need to divide the width of the interval by 2.

And now with the margin of error we can find the sample mean with any of the two following ways:

$12.6 +1.1=13.7$

$14.8-1.1=13.7$

So for this case the correct answer would be:

A. Sample Mean = 13.7; Margin of Error = 1.1

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".

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=85-1=84$

We know that the confidence interval is given by:

$12.6 < \mu < 14.8$

For this case we can find the margin of error like this:

$ME= \frac{14.8-12.6}{2}= 1.1$

Since we need to divide the width of the interval by 2.

And now with the margin of error we can find the sample mean with any of the two following ways:

$12.6 +1.1=13.7$

$14.8-1.1=13.7$

So for this case the correct answer would be:

A. Sample Mean = 13.7; Margin of Error = 1.1

3 0

3 years ago

Choose Yes or No to tell whether the expressions are equivalent.

netineya [11]

1. No
2. No
3. Yes
4. No, it’s actually 24j -36

8 0

3 years ago

I need help solving this problem

Elena L [17]

Use the given values in the compound interest formula to solve for time, n.

A is the final amount of money, $2800
P is the initial or starting amount $1900
i is the interest rate as a decimal 0.025
n is time in years since it annual.

2800 = 1900(1 + 0.025)^n

2800 = 1900(1.025)^n

2800/1900 = (1.025)^n

28/19 = (1.025)^n

take the natural log of both sides to solve for exponent.

ln(28/19) = ln(1.025^n)

power rule of logarithmic moves exponent

ln(28/19) = n*ln(1.025)

ln(28/19) / ln(1.025) = n

put into a calculator

15.7 years = n

4 0

3 years ago

In baseball, a player pitches a ball from the mound to a catcher behind the plate. A pitch that passes over the plate above the

elena-s [515]

The probability the pitch over the plate is a ball is 5:10. (5 balls and 10 strikes over the plate) should be written as 5:15 or 1:3 so this one is inaccurate.

4 0

3 years ago

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