Pls help and thank you!

Mathematics

2 answers:

lyudmila [28]2 years ago

8 0

Answer:

0.052 acre/min

Step-by-step explanation:

6 1/4 acres / 2 hours times the conversion factor (1 hr / 60 min) comes out to:

6.25

----------------- = 0.052 acre/min

2 (60 min)

---------

Natalka [10]2 years ago

7 0

She mows 6.25 acres in 2 hours. use d= rt . we want to know r so d equals 6.25 then divide t or two hours but change to minutes so 120 minutes and divide that into 6.25....don't forget to label the answer. per minute Layla mows (rounded) 0.05 acres/ minute.

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How many fractions are there between any two numbers on a number line?

klasskru [66]

Answer:

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Step-by-step explanation:

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2 years ago

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Researchers are interested if a school breakfast program leads to taller children. Assume that the population of all 5 year-old

DedPeter [7]

Answer:

$39-1.96\frac{1}{\sqrt{25}}=38.608$

$39+1.96\frac{1}{\sqrt{25}}=39.392$

So on this case the 95% confidence interval would be given by (38.608;39.392)

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

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".

$\bar X=39$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma=1$ represent the population standard deviation

n=25 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

The margin of error is given by:

$ME= z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a tabel to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$