Please help me. Ive needed help on this for a long time

Mrac [35]

F. Buying 4 bottles of Fresh All.

4 0

3 years ago

My brother wants to estimate the proportion of Canadians who own their house.What sample size should be obtained if he wants the

AVprozaik [17]

Answer:

a) $n=\frac{0.675(1-0.675)}{(\frac{0.02}{1.64})^2}=1475.07$

And rounded up we have that n=1476

b) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.64})^2}=1681$

And rounded up we have that n=1681

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".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

If solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Part a

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by $\alpha=1-0.9=0.1$ and $\alpha/2 =0.05$ . And the critical value would be given by:

$z_{\alpha/2}=\pm 1.64$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

And replacing into equation (b) the values from part a we got:

$n=\frac{0.675(1-0.675)}{(\frac{0.02}{1.64})^2}=1475.07$

And rounded up we have that n=1476

Part b

For this case since we don't have a prior estimate we can use $\hat p =0.5$

$n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.64})^2}=1681$

And rounded up we have that n=1681

8 0

3 years ago

The profits in hundreds of dollars, P(c), that a company can make from a product is modeled by a function of the price, c, they

Jobisdone [24]

The maximum profit is the y-coordinate of the vertex of the parabola represented by the equation.

$P(c)=-20c^2+320c+5120 \\ \\
a=-20 \\
b=320 \\ \\
\hbox{the vertex } (h,k): \\
h=\frac{-b}{2a}=\frac{-320}{2 \times (-20)}=\frac{-320}{-40}=8 \\
k=f(h)=f(8)=-20 \times 8^2+320 \times 8+5120= \\
=-1280+2560+5120=6400$

The maximum value is 6400, but the profit is given in hundreds of dollars, so multiply the value by 100.

The maximum profit the company can make is $640,000.

4 0

3 years ago

Read 2 more answers

Each morning librarians place 560 books on a book shelf in the school library. Each student that visits library that day takes e

Alex73 [517]

Answer:

Step-by-step explanation:

560=3s+b

b.

560=3×150+b

b=560-450=110

when s=149,b=560-3×149=560-447=113

s=2,b=560-3×2=560-6=554

s=1,b=560-3×1=557

s=0,b=560-3×o=560

so domain of b={110,113,116,...,554,557,560}

7 0

3 years ago

Sand and gravel are mixed in the ratio 5:3 to form ballast.

r-ruslan [8.4K]

<h3>Answer: 1250 kg of sand</h3>

Work Shown:

sand/gravel = 5/3

x/750 = 5/3

3x = 750*5

3x = 3750

x = 3750/3

x = 1250

8 0

2 years ago