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2 years ago

Jonathons piggy bank contains 20 nickels 30 quarters and 50 one dollar coins. He picks 20 coins from the bank at random

Mathematics

1 answer:

fredd [130]2 years ago

4 0

Answer:

All in all, Jonathan's piggy bank contains 100 coins. Among these coins, only 50 are one-dollar coins. Therefore, the theoretical probability of picking one-dollar coin from the piggy bank is equal to 50/100 or 1/2.

Similarly, from the experiment, 20 coins were picked and among these there are 12 one-dollar coins. The answer to the second question is therefore 12/20 or 3/5.

Step-by-step explanation:

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Cheryl wants to find the number of hours seventh-graders do homework each week. There are 297 boys and girls in seventh grade. I

Dafna1 [17]

There are a total of 297 students in the 7th grade. Rough estimates would say that about half of that number are boys and half are girls. Asking only 50 random girls would be biased because not only would it not be all of the girls (the number of girls would be around 148 or 149) but it would also be ignoring the roughly 148 to 149 boys there are on estimate. The sample would be biased because it would be ignoring the opinions of more than half the seventh grade.

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2 years ago

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All students are classified as either full-time or part-time. Kenneth conducted a survey in which he collected data on the perce

Crank

Answer:

Step-by-step explanation:

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2 years ago

A glass bead has the shape of a rectangular prism with a smaller rectangular prism removed. What is the volume of the glass that

olganol [36]

The volume of the removed portion is 35 cm³.

Step-by-step explanation:

Given,

The length× width× height (L×B×H) of the outer part = 3 cm×3 cm×7 cm

The length× width× height (l×b×h) of the inner part = 2 cm×2 cm×7 cm

To find the volume of the removed portion.

Formula

The volume of the removed portion = volume of outer part - volume of inner part

Volume of rectangular prism = l×b×h

Now,

Volume of outer part = 3×3×7 cm³ = 63 cm³

Volume of inner part = 2×2×7 cm³ = 28 cm³

Hence,

The volume of the removed portion = 63-28 cm³ = 35 cm³

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2 years ago

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a sports statistician claim that the mean winning times for boston marathon women's open division champions is at least 2.68 hou

GenaCL600 [577]

Answer:

We conclude that the mean winning times for Boston marathon women's open division champions is at least 2.68 hours.

Step-by-step explanation:

We are given that a sports statistician claim that the mean winning times for Boston marathon women's open division champions is at least 2.68 hours.

The mean winning time of a sample of 30 randomly selected Boston marathon women's open division champions is 2.60 hours. assume the population standard deviation is 0.32 hours.

Let $\mu$ = mean winning times for Boston marathon women's open division champions.

So, Null Hypothesis, $H_0$ : $\mu\geq$ 2.68 hours {means that the mean winning times for Boston marathon women's open division champions is at least 2.68 hours}

Alternate Hypothesis, $H_A$ : p < 2.68 hours {means that the mean winning times for Boston marathon women's open division champions is less than 2.68 hours}

The test statistics that would be used here One-sample z test statistics as we know about the population standard deviation;

T.S. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample mean winning time = 2.60 hours

$\sigma$ = population standard deviation = 0.32 hours

n = sample of women's open division champions = 30

So, test statistics = $\frac{2.60-2.68}{\frac{0.32}{\sqrt{30} } }$

= -1.37

The value of z test statistics is -1.37.

Now, P-value of the test statistics is given by following formula;

P-value = P(Z < -1.37) = 1 - P(Z $\leq$ 1.37)

= 1 - 0.9147 = 0.0853

Since, P-value of the test statistics is more than the level of significance as 0.0853 > 0.05, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which we fail to reject our null hypothesis.

Therefore, we conclude that the mean winning times for Boston marathon women's open division champions is at least 2.68 hours.

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2 years ago

Melissa buys 212 pounds of salmon and 114 pounds of swordfish. She pays a total of $31.25, and the swordfish costs $0.20 per pou

charle [14.2K]

Answer: b

Step-by-step explanation:

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2 years ago