What's the equation for this problem? Please help!! It's due tomarrow

If a length of a square is 3.2 cm square what is the perimeter and area

stiv31 [10]

Since all of a squares sides are the same length, we can use 3.2 cm in the following equations:

P= 2L + 2W and A= L x W

P= 2(3.2) + 2(3.2) which is the same as P= 4(3.2)

P= 12.8 cm

A= 3.2 x 3.2
A= 10.24 cm^2

3 0

2 years ago

A principal of a large high school wants to estimate the true proportion of high school students who use the community's public

denis-greek [22]

Considering the margin of error of a confidence interval, it is found that the correct option is:

It would be half as wide.

<h3>What is the margin of error of a confidence interval?</h3>

It is modeled by:

$M = z\frac{s}{\sqrt{n}}$

In which:

z is the critical value.

s is the standard deviation.

n is the sample size.

From this, we get that the margin of error is inversely proportional to the square root of the sample size. Then, multiplying the sample size by 4, when it changes from 50 to 200, cuts the margin of error in half, making the interval half as wide.

More can be learned about the margin of error of a confidence interval at brainly.com/question/25890103

5 0

3 years ago

The corner store sales peaches at a rate of three dollars per peach. If Vivian has $12 how many peach’s can Vivian buy?

mafiozo [28]

Answer:

4 peaches

Step-by-step explanation:

12/3=4

8 0

3 years ago

"Assuming a current world population of 8 billion people, an annual growth rate of 1.8% per year, and a worst-case scenario of e

Ganezh [65]

Answer:

The world population will be 11.64 billions in 21 years.

Step-by-step explanation:

Initial population = 8 billion

Growth rate = 1.8% per year =0.018

Time = 21 years

We are supposed to find what will the world population be in 21 years

Formula : $y = a (1+r)^t$

y = population after t years

r = rate of interest in decimals

t = time in years

Substitute the values :

$y =8(1+0.018)^{21}$

$y =11.635$

Hence the world population will be 11.64 billions in 21 years.

4 0

4 years ago

An advertising executive claims that there is a difference in the mean household income for credit cardholders of Visa Gold and

Maslowich

Answer:

Null hypothesis: $\mu_{Visa}=\mu_{Mastercard}$

Alternative hypothesis: $\mu_{Visa} \neq \mu_{Mastercard}$

$t=\frac{66970-59060}{\sqrt{\frac{9500^2}{11}+\frac{10000^2}{17}}}}=2.108$

$p_v =2*P(t_{26}>2.108)=0.0448$

Comparing the p value with the significance level given $\alpha=0.1$ we see that $p_v$ so we can conclude that we can reject the null hypothesis, and a would be a significant difference between the in the mean household income for credit cardholders of Visa Gold and of MasterCard Gold at 10% of significance .

Step-by-step explanation:

Data given and notation

$\bar X_{Visa}=66970$ represent the mean for Visa

$\bar X_{Mastercard}=59060$ represent the mean for the sample Mastercard

$s_{Visa}=9500$ represent the population standard deviation for Visa

$s_{Mastercard}=10000$ represent the population standard deviation for Mastercard

$n_{Visa}=11$ sample size for the group Visa

$n_{Mastercard}=17$ sample size for the group Mastercard

t would represent the statistic (variable of interest)

$\alpha=0.1$ significance level provided

Develop the null and alternative hypotheses for this study?

We need to conduct a hypothesis in order to check if the means for the two groups are different, the system of hypothesis would be:

Null hypothesis: $\mu_{Visa}=\mu_{Mastercard}$

Alternative hypothesis: $\mu_{Visa} \neq \mu_{Mastercard}$

Since we don't know the population deviations for each group, for this case is better apply a t test to compare means, and the statistic is given by:

$z=\frac{\bar X_{Visa}-\bar X_{Masterdcard}}{\sqrt{\frac{s^2_{Visa}}{n_{Visa}}+\frac{s^2_{Mastercard}}{n_{Mastercard}}}}$ (1)

t-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

Calculate the value of the test statistic for this hypothesis testing.

Since we have all the values we can replace in formula (1) like this:

$t=\frac{66970-59060}{\sqrt{\frac{9500^2}{11}+\frac{10000^2}{17}}}}=2.108$

What is the p-value for this hypothesis test?

First we need to calculate the degrees of freedom given by:

$df= n_{Visa}+n_{Mastercard}-2 = 11+17-2= 26$

Since is a bilateral test the p value would be:

$p_v =2*P(t_{26}>2.108)=0.0448$

Based on the p-value, what is your conclusion?

Comparing the p value with the significance level given $\alpha=0.1$ we see that $p_v$ so we can conclude that we can reject the null hypothesis, and a would be a significant difference between the in the mean household income for credit cardholders of Visa Gold and of MasterCard Gold at 10% of significance .

4 0

3 years ago