I dont understand :/

Water has a specific heat of 4.184 J/g°C and requires 23,000 J of heat to raise the

nasty-shy [4]

Answer:

$m=80.840 kg$

Step-by-step explanation:

Given Data,

Q=23000 J

c=4.184 J/g °c

Δt= 68 °c

m=?

By using this equation,

Q=mcΔt

$23000=m\times 4.184\times 68\\\\m=\frac{23000}{4.184\times68} \\\\\\m=80.840 kg$

3 0

2 years ago

A study was conducted to see if students given extra oxygen prior to taking the SAT could improve their scores. It was found tha

erik [133]

Answer:

Hypothesis testing of ' significance of difference between means'

Step-by-step explanation:

Study conducted to tests whether oxygen level prior SAT score improves test score. This can be done through - Hypothesis testing of ' significance of difference between means'.

Where x1 & x2 represent mean values of SAT test score before (or without) & after (or with) oxygen.

Null hypothesis [H0] = x1 = x2 , Alternate Hypothesis [H1] : x1 < x2

6 0

3 years ago

How do you divide 270 into 3000

chubhunter [2.5K]

3000
/ 270
______
11.111111111111111111111111r

r = reoccurring

4 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

What is 0.05 10 times as much as

Varvara68 [4.7K]

0.005
Multiplying by ten moves the decimal point over one.

6 0

2 years ago

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