How many lines of symmetry does this figure have<br> A 1<br> B, 2<br> C. 3<br> D, 4

A new crew of painters can paint a small apartment in 12 hours. an experienced crew can paint the small apartment in 6 hours. ho

Yakvenalex [24]

This is the concept of proportionality, we are required to calculate for the number of hours two crews can use to paint the house altogether.
Here proceed as follows;
number of hours new crew can paint=12 hrs
portion of work painted by new crew in 1 hour= 1/12

number of hours experienced crew can paint=6 hours
Portion of work painted by experienced crew in 1 hour=1/6

Portion of work painted by the two crews altogether in 1 hour will be:
1/6+1/12=1/4

thus the total amount of hours that the two painters will take to paint will be:
4 hours

6 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

What is 2.346 as a percent

34kurt

Answer:

Step-by-step explanation:

to turn a decimal to a percent, multiply by 100.....or if there is a decimal in there, start from the decimal and just move 2 spaces to the right.

2.346 = 234.6%

and just so you know, to turn a percent to a decimal, divide by 100...or move the decimal point 2 spaces to the left

6 0

3 years ago

HELP ME HOW DO I DO THIS ITS REALLY HARD

storchak [24]

Answer:

I can’t just tell you the answer cause that’s all your looking for let me know what u need help with

Step-by-step explanation:

4 0

2 years ago

Read 2 more answers

The domain of a function is?

Grace [21]

The correct answer is B) The set of all first elements of the function. Let's say you had these three points on a graph of a function: (0.9), (2.6), (4,7). The domain of these three points would be (0,2,4). The domain is just the input for which the function is defined. Hope this helps.

7 0

3 years ago

Read 2 more answers

How many lines of symmetry does this figure have A 1 B, 2 C. 3 D, 4