(3х + y= 23<br> 3х

1. The volume of a rectangular prism is the length multiplied by the

Dmitry [639]

Answer:

4ft

Step-by-step explanation:

Look at attached image for answer.

4 0

3 years ago

Amy can buy 5 shirts for a total of $25.How much would it cost if she were to buy 9 shirts at the same price?

Blababa [14]

Answer:

It would cost her $45.

Step-by-step explanation:

25 dollars divided by 5 shirts = 5 dollars per shirt.

5 dollars x 9 shirts = $45 dollars in total.

8 0

4 years ago

Read 2 more answers

The International Air Transport Association surveys business travelers to develop quality ratings for transatlantic gateway airp

ale4655 [162]

Answer:

$6.26-2.01\frac{2.47}{\sqrt{50}}=5.56$

$6.26+2.01\frac{2.47}{\sqrt{50}}=6.96$

So on this case the 95% confidence interval would be given by (5.56;6.96)

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".

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

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

Solution to the problem

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

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

In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (2)

$s=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar X)}{n-1}}$ (3)

The mean calculated for this case is $\bar X=6.26$

The sample deviation calculated $s=2.47$

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=50-1=49$

Assuming a Confidence of 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,49)".And we see that $t_{\alpha/2}=2.01$