• Evaluate 15 / (-3) + 5|1-21 / (-5)

Find the minimum sample size necessary to be 99% confident that the population mean is within 3 units of the sample mean given t

SVEN [57.7K]

Answer:

The minimum sample size required is 207.

Step-by-step explanation:

The (1 - α) % confidence interval for population mean μ is:

$CI=\bar x\pm z_{\alpha /2}\frac{\sigma}{\sqrt{n}}$

The margin of error of this confidence interval is:

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

Given:

$MOE=3\\\sigma=29\\z_{\alpha /2}=z_{0.01/2}=z_{0.05}=2.576$

*Use a z-table for the critical value.

Compute the value of n as follows:

$MOE=z_{\alpha /2}\frac{\sigma}{\sqrt{n}}\\3=2.576\times \frac{29}{\sqrt{n}} \\n=[\frac{2.576\times29}{3} ]^{2}\\=206.69\\\approx207$

Thus, the minimum sample size required is 207.

3 0

3 years ago

Reggie can line a football field in 120 minutes. Rosalinda can line a football field in 80 minutes. If they work together, how m

wel

Answer:

48 minutes

Step-by-step explanation:

Given that;

Rosalinda can line the football field in 80 minutes

Reggie can line the football field in 120 minutes

Lets assume that if they work together, they will take T minutes to line the football field

Hence;

Thus in 1 minute, Rosalina can line 1/80 of the field where as Reggie can line 1/120 of the field

$\frac{1}{T} =\frac{1}{120} +\frac{1}{80} \\\\\frac{1}{T} =\frac{2+3}{240}\\\\$

The sum of the two fractions will represent the size of the field that can be lined in 1 minute.

$\frac{1}{T} =\frac{5}{240} \\\\\frac{1}{T} =\frac{1}{48} \\T= 48$

The reciprocal of the sum of the two fractions will represent the time taken for both Rosalinda and Reggie to line the field.

Answer ; It will take them 48 minutes for them to line the football field

6 0

3 years ago

Read 2 more answers

Help please thanksssssssssssssssssssssssssssssssssssssssssssssssss

Oksanka [162]

Answer:

it is letter c.33.21 in³

4 0

3 years ago

Solve the system using substitution method 3x+y=6 2x-4y=10

Andreyy89

$\left\{\begin{array}{ccc}3x+y=6&|-3x\\2x-4y=10\end{array}\right\\\\\left\{\begin{array}{ccc}y=6-3x\\2x-4y=10\end{array}\right\\\\substitute\ y=6-3x\ to\ the\ second\ equation\\\\2x-4(6-3x)=10\\\\2x-4\cdot6-4\cdot(-3x)=10\\\\2x-24+12x=10\\\\14x-24=10\ \ \ |+24\\\\14x=34\ \ \ \ |:14\\\\x=\dfrac{34}{14}\to x=\dfrac{17}{7}\\\\substitute\ the\ value\ of\ x\ to\ first\ equation\\\\y=6-3\cdot\dfrac{17}{7}=6-\dfrac{51}{7}=\dfrac{42}{7}-\dfrac{51}{7}=-\dfrac{9}{7}$

$\boxed{\left\{\begin{array}{ccc}x=\dfrac{17}{7}\\\\y=-\dfrac{9}{7}\end{array}\right}$

5 0

3 years ago

Read 2 more answers

Identify the expression which represents the calculation “subtract 3 from 15, then divided by 6

matrenka [14]

Answer:

$\frac{15-3}{6}$

Step-by-step explanation:

You would start by writing the expression for “subtract 3 from 15", which would be $\frac{15-3}{6}$ , then you would add on "then divided by 6", which would make it

4 0

3 years ago

Read 2 more answers