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GuDViN [60]
3 years ago
9

Joses ACT score had a z-score of .75.what was his ACT score? mean score=21.1 sd=5.2

Mathematics
1 answer:
Zielflug [23.3K]3 years ago
6 0

Answer:

X \sim N(21.1,5.2)  

Where \mu=21.1 and \sigma=5.2

And the z score is given by:

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

And since z = 0.75 we can replace like this:

0.75 = \frac{x- 21.1}{5.2}

And if we solve for x we got:

x = 21.1 +0.75*5.2 = 25

Step-by-step explanation:

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".  

Solution to the problem

Let X the random variable that represent the ACT scores of a population, and for this case we know the distribution for X is given by:

X \sim N(21.1,5.2)  

Where \mu=21.1 and \sigma=5.2

And the z score is given by:

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

And since z = 0.75 we can replace like this:

0.75 = \frac{x- 21.1}{5.2}

And if we solve for x we got:

x = 21.1 +0.75*5.2 = 25

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Angelina_Jolie [31]

Answer:

The probability of observing a sample mean of x = 52 or greater from a sample size of 25 is 0.0000026

Step-by-step explanation:

Mean = \mu = 45

Population standard deviation =\sigma = 6

Sample size = n =25

Sample mean = \bar{x} = 52

We are supposed to find  the probability of observing a sample mean of x = 52 or greater from a sample size of 25 i.e.P(x\geq 52)

Z=\frac{x-\mu}{\frac{\sigma}{\sqrt{n}}}\\Z=\frac{52-45}{\frac{6}{\sqrt{25}}}

Z=5.83

P(Z<52)=0.9999974

P(Z\geq 52)=1-P(z

Hence  the probability of observing a sample mean of x = 52 or greater from a sample size of 25 is 0.0000026

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3 years ago
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Answer:

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Five buses leave on a field trip .There are about 45 students per bus.About how many students are on the 5 buses.
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7 0
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the peach festival charges $5 for admission then$1.25 per pound of peaches picked. If Savanna went to the festival and picked 2.
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Answer:

I'm glad you asked!

Step-by-step explanation:

So let's do it step by step.

Already she has to pay $5 for going in.

She has 2 whole pounds.

1.25 x 2=2.5 or 2 \frac{1}{2}

Add $5 and $ 2.5 .

5+2.5 = 7.5

Now let's do $1.25 divided by 10.

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Now let's do 0.125 times 4

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Now let's add 7.5 to 0.5

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Step-by-step explanation:

If Interest= Principal x rate x time/100; then time is (100 × Interest)/(Principal × Rate)

From the question, old Principal is 5600, new principal =6720, the difference is the interest accrued.

Interest = 6720 - 5600 = Rs 1120

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I hope this helps

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