I need the answer fast

A female cockroach can produce 80 offspring at a time. If half are female, and each female produces 80 offspring, how many cockr

IRINA_888 [86]

Ok if half are female that means 40 than 80 more for each of them because they all produce 80 so 80 times 40 = 3200 your gonna do the same 2 more times because of 3 generations so 3200 times 3 = 9600 in total

3 0

3 years ago

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David bought 3 dvds and 4 books for $40 at a yard sale. Anna bought 1 dvd and 6 books for $18. How much did each dvd and book co

Ber [7]

Answer:

A book is worth $1 and a DVD is worth $12.

Step-by-step explanation:

The equations (2 unknowns and two equations, d is for a DVD and b is for a book):

For David: 3d+4b=40

For Anna: d+6b=18

Now multiply the second equation with -3 and add to the first equation:

3d+4b=40

−3d−18b=−54

Combined equation: −14b=−14 and b=1 (means that each book is worth $1).

Now for DVD price, use the second equation:

d=18−6 or d=12 (means that each DVD is worth $12).

A book is worth $1 and a DVD is worth $12.

8 0

3 years ago

A study of the number of business lunches that executives in the insurance and banking industries claim as deductible expenses p

gizmo_the_mogwai [7]

Answer:

$t=\frac{9.1-8}{\sqrt{\frac{(1.9)^2}{40}+\frac{(2.1)^2}{50}}}}=2.604$

$p_v =2*P(t_{(88)}>2.604)=0.0108$

So the p value is a very low value and using any significance level for given $\alpha=0.05$ always $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and there is enough evidence to conclude that the two means are significantly different at 5%

Step-by-step explanation:

Data given and notation

$\bar X_{1}=9.1$ represent the mean for the sample 1

$\bar X_{2}=8$ represent the mean for the sample 2

$s_{1}=1.9$ represent the sample standard deviation for the sample 1

$s_{2}=2.1$ represent the sample standard deviation for the sample 2

$n_{1}=40$ sample size for the group 1

$n_{2}=50$ sample size for the group 2

t would represent the statistic (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to check if the mean are different , the system of hypothesis would be:

Null hypothesis: $\mu_{1} = \mu_{2}$

Alternative hypothesis: $\mu_{1} \neq \mu_{2}$

If we analyze the size for the samples both are higher than 30 and the population deviations are not given, so for this case is better apply a t test to compare means, and the statistic is given by:

$t=\frac{\bar X_{1}-\bar X_{2}}{\sqrt{\frac{s^2_{1}}{n_{1}}+\frac{s^2_{2}}{n_{2}}}}$ (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 statistic

We can replace in formula (1) the results obtained like this:

$t=\frac{9.1-8}{\sqrt{\frac{(1.9)^2}{40}+\frac{(2.1)^2}{50}}}}=2.604$

Statistical decision

The first step is calculate the degrees of freedom, on this case:

$df=n_{1}+n_{2}-2=40+50-2=88$

Since is a bilateral test the p value would be:

$p_v =2*P(t_{(88)}>2.604)=0.0108$

So the p value is a very low value and using any significance level for given $\alpha=0.05$ always $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and there is enough evidence to conclude that the two means are significantly different at 5%

3 0

2 years ago

Maria sells paintings in an art gallery. She earns $375 each week plus a commission equal to 2.5% of her sales. This week her is

Dennis_Churaev [7]

Answer:

im not 100% sure but i think its 9.375

Step-by-step explanation:

3 0

3 years ago

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R’(-1, 9) is the image of R after a reflection in the x-axis. What are the coordinates of R?

xz_007 [3.2K]

Answer:

Step-by-step explanation:

When we reflect over x-axis then the x-coordinate doesn't change and the y-coordinate changes its sign

in means if R = (x, y) then R' = (x, -y)

so we have:

x = -1 and -y = 9

y = -9

which gives R = (-1, -9)

6 0

2 years ago