PLEASE HELP ‍♀️‍♀️‍♀️‍♀️‍♀️‍♀️‍♀️‍♀️‍♀️‍♀️‍♀️‍♀️‍♀️

Sam collects baseball cards. He gave 6 cards to his brother. He then got 4 new cards from his father. Sam now has 12 cards. How

JulijaS [17]

Answer:

14

Step-by-step explanation:

If he had 14 then he gave away 6, he'd have 8. 8 plus 4 is 12. He had 14 before giving any away.

8 0

3 years ago

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In an examination of purchasing patterns of shoppers, a sample of 16 shoppers revealed that they spent, on average, $54 per hour

Lesechka [4]

Answer:

$54-1.64\frac{21}{\sqrt{16}}=45.39$

$54 +1.64\frac{21}{\sqrt{16}}=62.61$

So on this case the 90% confidence interval would be given by (45.39;62.61)

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".

$\bar X=54$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=21$ represent the sample standard deviation

n=16 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)

Since the Confidence is 0.90 or 90%, the value of $\alpha=1-0.9=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

Now we have everything in order to replace into formula (1):

$54-1.64\frac{21}{\sqrt{16}}=45.39$

$54 +1.64\frac{21}{\sqrt{16}}=62.61$

So on this case the 90% confidence interval would be given by (45.39;62.61)

4 0

3 years ago

A geometry fact that I find helpful. (Brainly, please don't take this down it is very educational)

sergeinik [125]

Answer:

Thank you so much for this

Step-by-step explanation:

Have a nice day ! :)

5 0

2 years ago

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I NEED HELP PLS I WILL MARK BRAINLIEST

ANEK [815]

Answer:

$\approx 11.2\:\mathrm{in}$

Step-by-step explanation:

The swing of the tip of pendulum is creating an arc. The question is actually asking for the length of this arc. The length of an arc is given by $2r\pi\cdot \frac{\theta}{360}$ , where $r$ is the radius of the circle and $\theta$ is the angle of the arc.