All categories

3 years ago

P L E A S E H E L P A S A P !!!

Mathematics

1 answer:

natulia [17]3 years ago

8 0

Answer:

The third one for the first picture and the second one for the second picture

Step-by-step explanation:

You might be interested in

Two catalysts may be used in a batch chemical process. Twelve batches were prepared using catalyst 1, resulting in an average yi

aalyn [17]

Answer:

a) $t=\frac{(91-85)-(0)}{2.490\sqrt{\frac{1}{12}}+\frac{1}{15}}=6.222$

$df=12+15-2=25$

$p_v =P(t_{25}>6.222) =8.26x10^{-7}$

So with the p value obtained and using the significance level given $\alpha=0.01$ we have $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

b) $(91-85) -2.79 *2.490 \sqrt{\frac{1}{12} +\frac{1}{15}} =3.309$

$(91-85) +2.79 *2.490 \sqrt{\frac{1}{12} +\frac{1}{15}} =8.691$

Step-by-step explanation:

Notation and hypothesis

When we have two independent samples from two normal distributions with equal variances we are assuming that

$\sigma^2_1 =\sigma^2_2 =\sigma^2$

And the statistic is given by this formula:

$t=\frac{(\bar X_1 -\bar X_2)-(\mu_{1}-\mu_2)}{S_p\sqrt{\frac{1}{n_1}}+\frac{1}{n_2}}$

Where t follows a t distribution with $n_1+n_2 -2$ degrees of freedom and the pooled variance $S^2_p$ is given by this formula:

$\S^2_p =\frac{(n_1-1)S^2_1 +(n_2 -1)S^2_2}{n_1 +n_2 -2}$

This last one is an unbiased estimator of the common variance $\sigma^2$

Part a

The system of hypothesis on this case are:

Null hypothesis: $\mu_2 \leq \mu_1$

Alternative hypothesis: $\mu_2 > \mu_1$

Or equivalently:

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

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

Our notation on this case :

$n_1 =12$ represent the sample size for group 1

$n_2 =15$ represent the sample size for group 2

$\bar X_1 =85$ represent the sample mean for the group 1

$\bar X_2 =91$ represent the sample mean for the group 2

$s_1=3$ represent the sample standard deviation for group 1

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

First we can begin finding the pooled variance:

$\S^2_p =\frac{(12-1)(3)^2 +(15 -1)(2)^2}{12 +15 -2}=6.2$

And the deviation would be just the square root of the variance:

$S_p=2.490$

Calculate the statistic

And now we can calculate the statistic:

$t=\frac{(91-85)-(0)}{2.490\sqrt{\frac{1}{12}}+\frac{1}{15}}=6.222$

Now we can calculate the degrees of freedom given by:

$df=12+15-2=25$

Calculate the p value

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

$p_v =P(t_{25}>6.222) =8.26x10^{-7}$

Conclusion

So with the p value obtained and using the significance level given $\alpha=0.01$ we have $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

Part b

For this case the confidence interval is given by:

$(\bar X_1 -\bar X_2) \pm t_{\alpha/2} S_p \sqrt{\frac{1}{n_1} +\frac{1}{n_2}}$

For the 99% of confidence we have $\alpha=1-0.99 = 0.01$ and $\alpha/2 =0.005$ and the critical value with 25 degrees of freedom on the t distribution is $t_{\alpha/2}= 2.79$

And replacing we got:

$(91-85) -2.79 *2.490 \sqrt{\frac{1}{12} +\frac{1}{15}} =3.309$

$(91-85) +2.79 *2.490 \sqrt{\frac{1}{12} +\frac{1}{15}} =8.691$

7 0

3 years ago

Hhellp pwease I want to know what's wrong and right

Studentka2010 [4]

Answer:

A: False

B: False

C: True

D: True

E: False

F: True

G: True

H: True

Step-by-step explanation:

A: 9(x - 2) = 9x + 2

9x - 18 = 9x + 2 FALSE

B: 65 - y = y - 65

(equation rearranged) -y + 65 = y - 65 FALSE

C: g (times) h = h (times) g (TRUE due to the commutative property of multiplication)

D: a (times) 0 = 0 (TRUE because anything times 0 equals 0)

E: (4 (times) 2) - r = 4 (2 (times) r)

8 - r = 8 - 4r FALSE

F: k + 0 = k TRUE

G: (a + x) + y = a + (x + y)

a + x + y = a + x + y TRUE

H: 5(2x - 9) = 10x - 45

10x - 45 = 10x - 45 TRUE

6 0

3 years ago

PLEASE HELP WILL MARK BRAINLIEST

Ivanshal [37]

First one pretty obvious

8 0

3 years ago

Heather invested $11,600 in an account that pays 5% simple interest. If she invests the money for 6 years, how much will she hav

melisa1 [442]

The amount she will receive after 6 years
=$11600*(1+5%*6)
=$11600*1.3
=$15080

4 0

2 years ago

Read 2 more answers

What is the change in value of the 5 digit in these two numbers? 658 201 and 675 201

Rashid [163]

The change in value of the 5th digit is, 2.

50,000 to 70,000. Which is an addition of 20,000

3 0

4 years ago