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4 years ago

Someone please help me with this question. I would greatly appreciate it. Please and thank you.

Mathematics

1 answer:

Sladkaya [172]4 years ago

6 0

$\dfrac{15(15-1)}{2}=\dfrac{15\cdot14}{2}=15\cdot7=105$

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3 years ago

Can someone help me solve this?

julsineya [31]

Answer:

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3 years ago

Joy has ₱500.00 to spend for food. She spent ₱98.75 on Monday, ₱73.75 on Tuesday and ₱50.25 on Wednesday. How much money was lef

Alex787 [66]

Answer:

₱277.25

Step-by-step explanation:

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3 years ago

a coin is tossed, then a letter in the word accomplishment is chosen at random. find the probability of heads, then a vowel

emmasim [6.3K]

Answer:

$\frac{5}{52}$

Step-by-step explanation:

Coin toss:

$Total\ outcome=\{H,T\}\\\\Favourable\ outcome=\{H\}\\\\P(Head)=\frac{Favourable\ outcome}{Number\ of\ total\ outcome}\\\\P(Head)=\frac{1}{2}$

Letter Selection:

$Number\ of\ total\ outcomes=26\ \ \ \ \ \ \ as\ total\ letters\ are\ 26\\\\Favourable\ outcomes=5\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ as\ there\ are\ 5\ vowels\\\\P(vowel)=\frac{Favourable\ outcomes}{Number\ of\ total\ outcomes}\\\\P(vowel)=\frac{5}{26}$

$These\ two\ events\ are\ independent.\\\\Hence\ probability\ of\ head\ and\ then\ vowel=\frac{1}{2}\times \frac{5}{26}=\frac{5}{52}$

4 0

3 years ago

The U.S. and many other countries have recently tightened airport security. A sociologist is interested in estimating the propor

melisa1 [442]

Answer:

0.0073 < 0.05, which means that we reject the null hypothesis and conclude that the true proportion of interest is higher than 0.7.

Step-by-step explanation:

Conduct a test to determine whether the true proportion of interest is higher than 0.7.

This means that the null hypothesis is: $H_{0}: p = 0.7$

And the alternate hypothesis is: $H_{a}: p > 0.7$

The test statistic is:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

In which X is the sample mean, $\mu$ is the value tested at the null hypothesis, $\sigma$ is the standard deviation and n is the size of the sample.

0.7 is tested at the null hypothesis:

This means that $\mu = 0.7, \sigma = \sqrt{0.7*0.3}$

The sociologist found that 375 of the 500 travelers randomly selected and interviewed indicated that the airports were safe.

This means that $n = 500, X = \frac{375}{500} = 0.75$

Value of the z-statistic:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

$z = \frac{0.75 - 0.7}{\frac{\sqrt{0.7*0.3}}{\sqrt{350}}}$

$z = 2.44$

P-value of the test:

Probability of z being larger than 2.44, that is, a proportion larger than 0.75.

This is, looking at the z-table, 1 subtracted by the pvalue of Z = 2.44. S

Z = 2.44 has a pvalue of 0.9927

1 - 0.9927 = 0.0073

0.0073 < 0.05, which means that we reject the null hypothesis and conclude that the true proportion of interest is higher than 0.7.

8 0

3 years ago