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kow [346]
2 years ago
15

Previously, an organization reported that teenagers spent 4.5 hours per week, on average, on the phone. The organization thinks

that, currently, the mean is higher. Fifteen randomly chosen teenagers were asked how many hours per week they spend on the phone. The sample mean was 4.75 hours with a sample standard deviation of 2.0. Conduct a hypothesis test.
Mathematics
1 answer:
kiruha [24]2 years ago
3 0

The standard normal distribution is a special type of normal distribution where the mean is 0, and the standard deviation is 1. The hypothesis can not be concluded.

<h3>What is Standard normal distribution?</h3>

The standard normal distribution is a special type of normal distribution where the mean is 0, and the standard deviation is 1.

For the given problems, the Hypothesis mean is 4.5. The sample mean was 4.75 hours with a normal standard deviation of 2.0.

Now, calculating the z-score,

z = \dfrac{\bar x - \mu_o}{\dfrac{\sigma}{\sqrt n}}\\\\\\z = \dfrac{4.75-4.5}{\dfrac{2}{\sqrt{15}}}\\\\\\z = 0.48

Now, as per the standard normal table, the p-value is 0.6844. Since the p-value is greater than the significance level, the hypothesis can not be concluded.

Hence, The hypothesis can not be concluded.

Learn more about Standard normal distribution:

brainly.com/question/25447725

#SPJ1

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Step-by-step explanation:

First you need to find the area of the box which would be

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The second step wpuld be to divide the area of the box by how tall the cups are

180/3 = 60

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Which set of shapes could be used to form a net for a square pyramid?
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Answer:

A.1 square and 4 triangles

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A net is given in the attached diagram:

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Researchers at a pharmaceutical company have found that the effective time duration of a safe dosage of pain relief drug is norm
FrozenT [24]

Answer:

a) P(1

b) P(X

Step-by-step explanation:

1) Previous concepts

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".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".  

2) Part a

Let X the random variable that represent the duration of a safe dosage of pain relief drug, and for this case we know the distribution for X is given by:

X \sim N(1.5,0.8)  

Where \mu=1.5 and \sigma=0.8

We are interested on this probability

P(1

And the best way to solve this problem is using the normal standard distribution and the z score given by:

z=\frac{x-\mu}{\sigma}

If we apply this formula to our probability we got this:

P(1

And we can find this probability on this way:

P(-0.625

And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.  

P(-0.625

3) Part b

We are interested on this probability

P(X

And the best way to solve this problem is using the normal standard distribution and the z score given by:

z=\frac{x-\mu}{\sigma}

If we apply this formula to our probability we got this:

P(X

And we can find this probability on this way:

P(z

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3 years ago
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