Please help answer these math question will give brainless.. :)

Evaluate the expression 3.14(a2 + ab) when a = 4 and b = 3. (Input decimals only, such as 12.71, as the answer.)

Natasha2012 [34]

Answer:

87.92

Step-by-step explanation:

3.14(a² + ab) where a = 4 and b = 3

Plug the given numbers into the appropriate values. Remember to follow PEMDAS.

3.14((4)² + (4)(3))

3.14(16 + 12)

3.14(28)

87.92

5 0

3 years ago

Find the length of AB. Leave

vovikov84 [41]

Answer:

AB = 3π

Step-by-step explanation:

See attachment for correct format of question.

Given

From the attachment, we have that

θ = 20°

Radius, r = 27

Required

Find length of AB

AB is an arc and it's length can be calculated using arc length formula.

$Length = \frac{\theta}{360} * 2\pi r$

Substitute 20 for θ and 27 for r

$Length = \frac{20}{360} * 2\pi *27$

$Length = \frac{20 * 2\pi * 27}{360}$

$Length = \frac{1080 \pi}{360}$

$Length = 3\pi$

Hence, the length of arc AB is terms of π is 3π

3 0

3 years ago

A medical researcher wondered if there is a significant difference between the mean birth weight of boy and girl babies. Random

Yuliya22 [10]

Answer:

b) independent samples t-test

$t=\frac{(5.92 -5.74)-(0)}{\sqrt{\frac{1.88^2}{5}}+\frac{1.81^2}{5}}=0.154$

$p_v =2*P(t_{8}>0.154) =0.881$

So with the p value obtained and using the significance level given $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the mean of the group 1 (boys) is NOT significantly different than the mean for the group 2 (Girls).

Step-by-step explanation:

The system of hypothesis on this case are:

Null hypothesis: $\mu_1 = \mu_2$

Alternative hypothesis: $\mu_1 \neq \mu_2$

Or equivalently:

Null hypothesis: $\mu_1 - \mu_2 = 0$

Alternative hypothesis: $\mu_1 -\mu_2\neq 0$

Our notation on this case :

$n_1 =5$ represent the sample size for group 1

$n_2 =5$ represent the sample size for group 2

We can calculate the mean and deviation for eaach group with the following formulas:

$\bar X= \frac{\sum_{i=1}^n X_i}{n}$

$s = \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

$\bar X_1 =5.92$ represent the sample mean for the group 1

$\bar X_2 =5.74$ represent the sample mean for the group 2

$s_1=1.88$ represent the sample standard deviation for group 1

$s_2=1.81$ represent the sample standard deviation for group 2

If we see the alternative hypothesis we see that we are conducting a bilateral test and with independnet samples t test.

b) independent samples t-test

The statistic is given by this formula:

$t=\frac{(\bar X_1 -\bar X_2)-(\mu_{1}-\mu_2)}{\sqrt{\frac{s^2_1}{n_1}}+\frac{S^2_2}{n_2}}$

And now we can calculate the statistic:

$t=\frac{(5.92 -5.74)-(0)}{\sqrt{\frac{1.88^2}{5}}+\frac{1.81^2}{5}}=0.154$

The degrees of freedom are given by:

$df=5+5-2=8$

And now we can calculate the p value using the altenative hypothesis:

$p_v =2*P(t_{8}>0.154) =0.881$

So with the p value obtained and using the significance level given $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the mean of the group 1 (boys) is NOT significantly different than the mean for the group 2 (Girls).

7 0

3 years ago

A house on the market was valued for 409,000

Nana76 [90]

I’d need to know the question to answer this.

5 0

3 years ago

Please answer this question asap

lukranit [14]

Answer:

Use the formula

P(X,y) ___y=x__(Reflection)_____P'(y,x)

I think it will help you.

8 0

2 years ago