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2 years ago

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When Brooklyn runs the 400 meter dash, her finishing times are normally distributed with a mean of 76 seconds and a standard dev

iation of 3 seconds. Using the empirical rule, what percentage of races will her finishing time be between 70 and 82 seconds?

1 answer:

KonstantinChe [14]2 years ago

3 0

Using the Empirical Rule, it is found that her finishing time will be between 70 and 82 seconds in 95% of her races.

<h3>What does the Empirical Rule state?</h3>

It states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

In this problem, the mean is of 76 seconds and the standard deviation is of 3 seconds, then:

76 - 2 x 3 = 70.

76 + 2 x 3 = 82.

Which means that values between 70 and 82 seconds are within 2 standard deviations of the mean, hence the percentage is of 95%.

More can be learned about the Empirical Rule at brainly.com/question/24537145

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My mother used 3/5 of a box of 35 eggs estimate how much sh used

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She used 21 eggs~

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In a game called Taxation and Evasion, a player rolls a pair of dice. If, on any turn, the sum is 7, 11, or 12, the player gets

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Answer:

$Probability = \frac{243}{1024}$

Step-by-step explanation:

Given

$Sum = \{7, 11, 12\}$

$Rolls = 5$

Required

Probability of not getting audited

If a pair of dice is rolled, the following are the observations of the sum

$Outcomes = 36$

$Sum\ of\ 7 = 6$

$Sum\ of\ 11 = 2$

$Sum\ of\ 12 = 1$

So, in a single roll; The probability of getting audited is:

$p= \frac{1 + 2 + 6}{36}$

$p= \frac{9}{36}$

$p= \frac{1}{4}$

The probability of not getting audited in a single roll is:

$q = 1 - p$ --- Complement rule

$q = 1 - \frac{1}{4}$

Take LCM

$q = \frac{4 - 1}{4}$

$q = \frac{3}{4}$

The probability of not getting audited in 5 rolls is:

$Probability = q^5$

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3 years ago

Find the surface area of the solid generated by revolving the region bounded by the graphs of y = x2, y = 0, x = 0, and x = 2 ab

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Answer:

See explanation

Step-by-step explanation:

The surface area of the solid generated by revolving the region bounded by the graphs can be calculated using formula

$SA=2\pi \int\limits^a_b f(x)\sqrt{1+f'^2(x)} \, dx$

If $f(x)=x^2,$ then

$f'(x)=2x$

and

$b=0\\ \\a=2$

Therefore,

$SA=2\pi \int\limits^2_0 x^2\sqrt{1+(2x)^2} \, dx=2\pi \int\limits^2_0 x^2\sqrt{1+4x^2} \, dx$

Apply substitution

$x=\dfrac{1}{2}\tan u\\ \\dx=\dfrac{1}{2}\cdot \dfrac{1}{\cos ^2 u}du$

Then

$SA=2\pi \int\limits^2_0 x^2\sqrt{1+4x^2} \, dx=2\pi \int\limits^{\arctan(4)}_0 \dfrac{1}{4}\tan^2u\sqrt{1+\tan^2u} \, \dfrac{1}{2}\dfrac{1}{\cos^2u}du=\\ \\=\dfrac{\pi}{4}\int\limits^{\arctan(4)}_0 \tan^2u\sec^3udu=\dfrac{\pi}{4}\int\limits^{\arctan(4)}_0(\sec^3u+\sec^5u)du$

Now

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Answer:

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Null Hypothesis: $p =0.44$

Alternative hypothesis: $p \neq 0.44$

Step-by-step explanation:

Previous concepts

A hypothesis is defined as "a speculation or theory based on insufficient evidence that lends itself to further testing and experimentation. With further testing, a hypothesis can usually be proven true or false".

The null hypothesis is defined as "a hypothesis that says there is no statistical significance between the two variables in the hypothesis. It is the hypothesis that the researcher is trying to disprove".

The alternative hypothesis is "just the inverse, or opposite, of the null hypothesis. It is the hypothesis that researcher is trying to prove".

Solution to the problem

For this case we want to conduct a test in order to see if the proportion of Clemson students who eat breakfast is different from 0.44 (alternative hypothesis). And the complement would represent the null hypothesis, and the system of hypothesis for this case are:

Null Hypothesis: $p =0.44$

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