Jerold put a desk in his bedroom. The picture shows where he put the desk. What is the area of the desk?

A mixture of compounds X and Y in a 0.100-cm cell had an absorbance of 0.215 at 272 nm and 0.191 at 327 nm. Find [X] and [Y] in

Oksi-84 [34.3K]

Answer: The concentration of X is $7.13582\times 10^{-6}$ and the concentration of Y is $2.53159\times 10^{-5}$ .

Step-by-step explanation:

Since we have given that

At 272 nm, absorbance = 0.215

At 327 nm, absorbance = 0.191

As we have given that

Compound X Compound Y

272 16400 3870

327 3990 6420

So, our equations becomes

$16400C_1+3870c_2=0.215\\\\3990C_1+6420C_2=0.191$

By solving these two equations, we get that

$C_1=7.13582\times 10^{-6}\\\\C_2=2.53159\times 10^{-5}$

Hence, the concentration of X is $7.13582\times 10^{-6}$ and the concentration of Y is $2.53159\times 10^{-5}$ .

5 0

3 years ago

g A certain financial services company uses surveys of adults age 18 and older to determine if personal financial fitness is cha

leva [86]

Answer:

Null hypothesis: $p_{1} = p_{2}$

Alternative hypothesis: $p_{1} \neq p_{2}$

$z=\frac{0.410-0.35}{\sqrt{0.385(1-0.385)(\frac{1}{1000}+\frac{1}{700})}}=2.502$

$p_v =2*P(Z>2.502)= 0.0123$

Comparing the p value with the significance level assumed $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to to reject the null hypothesis, and we can say that the proportion analyzed is significantly different between the two groups at 5% of significance.

Step-by-step explanation:

Data given and notation

$X_{1}=410$ represent the number of people indicating that their financial security was more than fair for the recent year

$X_{2}=245$ represent the number of people indicating that their financial security was more than fair for the year before

$n_{1}=1000$ sample 1 selected

$n_{2}=700$ sample 2 selected

$p_{1}=\frac{410}{1000}=0.410$ represent the proportion estimated of indicating that their financial security was more than fair this year

$p_{2}=\frac{245}{700}=0.35$ represent the proportion estimated of indicating that their financial security was more than fair the year before

$\hat p$ represent the pooled estimate of p

z would represent the statistic (variable of interest)

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

$\alpha$ significance level given

Concepts and formulas to use

We need to conduct a hypothesis in order to check if is there is a difference between the two proportions, the system of hypothesis would be:

Null hypothesis: $p_{1} = p_{2}$

Alternative hypothesis: $p_{1} \neq p_{2}$

We need to apply a z test to compare proportions, and the statistic is given by:

$z=\frac{p_{1}-p_{2}}{\sqrt{\hat p (1-\hat p)(\frac{1}{n_{1}}+\frac{1}{n_{2}})}}$ (1)

Where $\hat p=\frac{X_{1}+X_{2}}{n_{1}+n_{2}}=\frac{410+245}{1000+700}=0.385$

z-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

Calculate the statistic

Replacing in formula (1) the values obtained we got this:

$z=\frac{0.410-0.35}{\sqrt{0.385(1-0.385)(\frac{1}{1000}+\frac{1}{700})}}=2.502$

Statistical decision

Since is a two sided test the p value would be:

$p_v =2*P(Z>2.502)= 0.0123$

Comparing the p value with the significance level assumed $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to to reject the null hypothesis, and we can say that the proportion analyzed is significantly different between the two groups at 5% of significance.

7 0

3 years ago

Write an expression to match the description: 2 less than y

AveGali [126]

<h3>Answer:</h3>

y - 2

<h3>Step-by-step explanation:</h3>

You get 2 less than a value when you subtract 2 from that value.

3 0

3 years ago

A) Solve the system by substitution.<br> y = 5x – 3<br> -X – 5y = -11

Katen [24]

Answer:

Step-by-step explanation:

the answer 4x-5y +2 = 0. 5y =-4x-2. y = -4x/5 -2/5 slope = -4/5

8 0

2 years ago

Read 2 more answers

HELP WILL NAME BRAINLIEST: <br> Describe and correct the error.

Aleksandr-060686 [28]

Answer:

It should be congruent by the AAS congruence theorem

Step-by-step explanation:

The error is in the congruence theorem.

We know that the 2 angles are congruent and one of the sides are congruent. This means that it can either be congruent by ASA or AAS.

It is actually congruent by AAS because it include two angles and the side is opposite of one of the angles.

7 0

2 years ago