16 ÷ (2 + 1/2) ^2<br> 2 14/25<br> 4 1/4<br> 6 2/5<br> 8 1/4

Dave has a board that is 29 inches long.

elena-s [515]

For this question, you have to divide 29 into 4 pieces. To do this, divide 29 by 4 which is 7.25. So, each piece will be 7.25 inches long.

Hope it helps :)

4 0

3 years ago

Read 2 more answers

The area of land that Rhode Island covers is approximately 1.5X10^3 square miles. The area of land that Alaska covers is a littl

Katarina [22]

You just multiply 1.5x10^3 by 4.3x10^2. 1.5x10^3 is equal to 1500 (move the decimal to the right as many spaces as the exponent gives) and 4.3x10^2 is equal to 430. 1500*430=645000. To get that back down to scientific notation, we would have to move the decimal back to between the 6 and 4 to get 6.45 (Zeros aren't included in scientific notation) We moved the decimal to the left five spaces do the exponent is 10^5. We are left with 6.45x10^5

4 0

4 years ago

The sum of twice a number and 12 is no less than 24

noname [10]

The answer is 12 + 12 = 24

3 0

3 years ago

teachers at belleville elementary school asked students to name their favorite desserts. 3/8 candy, 1/4 ice cream, 1/8 pudding,

Evgesh-ka [11]

Answer:

7

Step-by-step explanation:

1/4 of 56 is 14

1/4 ice cream + 1/4 cookies is 28

1/8 of 56 is 7 so 7×3 =21

28+21=49

49+7=56

You divide the total number by the denominator so like 56÷8 is 7 and 56÷4 is 14.

7 0

3 years ago

Unfortunately, arsenic occurs naturally in some ground water†. A mean arsenic level of μ = 8.0 parts per billion (ppb) is consid

riadik2000 [5.3K]

Answer:

$t=\frac{7.2-8}{\frac{2.1}{\sqrt{41}}}=-2.439$

$p_v =P(t_{(40)}$

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and the true mean is lower than 8 ppb at 1% of signficance. We need to be careful with this interpretation since the p value is near to the significance level.

Step-by-step explanation:

Data given and notation

$\bar X=7.2$ represent the mean height for the sample

$s=2.1/tex] represent the sample standard deviation [tex]n=41$ sample size

$\mu_o =8$ represent the value that we want to test

$\alpha=0.01$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean is less than 8, the system of hypothesis would be:

Null hypothesis: $\mu \geq 8$

Alternative hypothesis: $\mu < 8$

If we analyze the size for the sample is > 30 but we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{7.2-8}{\frac{2.1}{\sqrt{41}}}=-2.439$

P-value

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

$df=n-1=41-1=40$

Since is a one side test the p value would be:

$p_v =P(t_{(40)}$

Conclusion

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and the true mean is lower than 8 ppb at 1% of signficance. We need to be careful with this interpretation since the p value is near to the significance level.

4 0

4 years ago

16 ÷ (2 + 1/2) ^2 2 14/25 4 1/4 6 2/5 8 1/4