What is -4.15 as a fraction

Please help me don't put nothing if you really don't kno it

USPshnik [31]

Answer:

Step-by-step explanation:

u didn't write anything

7 0

3 years ago

If 3 equals x over 3.3 what is x

Nana76 [90]

It’s 9.9 because 3 times 3.3 is 9.9

3 0

3 years ago

A genetic experiment involving peas yielded one sample of offspring consisting of 420 green peas and 174 yellow peas. Use a 0.01

slavikrds [6]

Answer:

a) $z=\frac{0.293 -0.23}{\sqrt{\frac{0.23(1-0.23)}{594}}}=3.649$

b) For this case we need to find a critical value that accumulates $\alpha/2$ of the area on each tail, we know that $\alpha=0.01$ , so then $\alpha/2 =0.005$ , using the normal standard table or excel we see that:

$z_{crit}= \pm 2.58$

Since the calculated value is higher than the critical value we have enough evidence to reject the null hypothesis at 1% of significance.

Step-by-step explanation:

Data given and notation

n=420+174=594 represent the random sample taken

X=174 represent the number of yellow peas

$\hat p=\frac{174}{594}=0.293$ estimated proportion of yellow peas

$p_o=0.23$ is the value that we want to test

$\alpha=0.01$ represent the significance level

Confidence=99% or 0.99

z would represent the statistic (variable of interest)

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

Concepts and formulas to use

We need to conduct a hypothesis in order to test the claim that the true proportion of yellow peas is 0.23:

Null hypothesis: $p=0.23$

Alternative hypothesis: $p \neq 0.23$

When we conduct a proportion test we need to use the z statisitc, and the is given by:

$z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}$ (1)

The One-Sample Proportion Test is used to assess whether a population proportion $\hat p$ is significantly different from a hypothesized value $p_o$ .

Calculate the statistic

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

$z=\frac{0.293 -0.23}{\sqrt{\frac{0.23(1-0.23)}{594}}}=3.649$

Statistical decision

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.

The significance level provided $\alpha=0.05$ . The next step would be calculate the p value for this test.

Since is a bilateral test the p value would be:

$p_v =2*P(z>3.649)=0.00026$

So the p value obtained was a very low value and using the significance level given $\alpha=0.05$ we have $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

b) Critical value

For this case we need to find a critical value that accumulates $\alpha/2$ of the area on each tail, we know that $\alpha=0.01$ , so then $\alpha/2 =0.005$ , using the normal standard table or excel we see that:

$z_{crit}= \pm 2.58$

Since the calculated value is higher than the critical value we have enough evidence to reject the null hypothesis at 1% of significance.

5 0

3 years ago

Simplify (5n^4)^−3. Assume n ≠ 0.

tekilochka [14]

Since the exponent (-3) is negative, flip the expression to: 1/(5n^4)^3.

Notice how the negative exponent becomes positive as you flip it.

Now evaluate the powers in the denominator: 1/((5^3)(n^4)^3

I separated the constant (5) from the variable (n) to show you how the powers are evaluated.

1/(5x5x5)(nxnxnxn)(nxnxnxn)(nxnxnxn)
—-> the power four means that there are 4 multiples of n in the parentheses. The power 3 corresponds to how many groups.

1/(125)(n^12)

= 1/125n^12

6 0

3 years ago

A gravel path is to be built around an 18‘ x 15‘ rectangle garden if the width remains constant how why can the path be if there

Ilia_Sergeevich [38]

Answer:

P = 2*(18 + 13) = 62ft

Now to figure out the width of the path we have to do some geometry. There are 3 basic shapes we will use for the path, they are the 13 ft long rectangle, the 18 ft long rectangle, and the squares formed at the corners. These squares' areas are equal to the width squared, whereas the rectangles are only equal to the length times the width. Our total area then becomes:

A = 2*(13*w) + 2*(18*w) + 4*(w*w)

A = 4w^2 + 62w

And since we know the available area is 516 ft^2, putting this in for A and solving the quadratic equation we can get the width:

516 = 4w^2 + 62w

0 = 4w^2 + 62w - 516

Using the quadratic formula: (w = -b2+/-SQRT(b^2 - 4ac)/2a, where a = 4, b = 62, and c = -516)

w = 6, -21.5

Since we obviously cannot have a negative width, 6 must be our answer. Therefore the path can be 6 feet wide!

We can check this answer by doing the following. Please note that by having a 6ft wide path you would actually be adding 12 ft to both dimensions, since you add 6 feet of length to both sides. Your total area would then become:

18+(2*6) x 13+(2*6) = 30x25 = 750 ft^2

Subtracting the area of the garden gives you the are of the gravel required:

750ft^2 - (18*13)ft^2 = 516ft^2

Therefore a width of 6 feet is correct.

Step-by-step explanation:

6 0

3 years ago

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