Number 76 nunber 77 number 78and 79 please

Help please, I have all the work I just don't understand part B

ollegr [7]

Answer is b the answer is because there is no C or D in my conversations are in my store

4 0

3 years ago

Julie goes shopping complete the following table to show his shopping bill

Murrr4er [49]

Answer:

£75.53

Step-by-step explanation:

3tshirt=£17.82

2pauntbrush=£13.94

4bags of pasta=£3.52

toral=£17.82+£13.94+£3.52+£41.25=75.53

4 0

2 years ago

What happens to the interval as the level of confidence is changed? Explain why this is a logical result.

Elan Coil [88]

Answer with explanation:

A x% confidence interval interprets the percentage of certainty that a person can believe that the true population parameter.

It is also represented as Point estimate ± Margin of error

Confidence level is proportional to the Margin of error.

As confidence level increases the error bound increases that makes the confidence interval broader.
As confidence level decreases the error bound decreases , making the confidence interval narrower.

6 0

2 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

HURRY UP PLEASE !!

IRISSAK [1]

Answer:

<h2>The x-interecepts are 5.6 and -1.4, approximately.</h2>

Step-by-step explanation:

The given equation is

$5x^{2} -21x=39$

Where $a=5$ , $b=-21$ and $c=39$ , let's use the quadratic formula

$x_{1,2}=\frac{-b(+-)\sqrt{b^{2}-4ac } }{2a} =\frac{-(-21) (+-)\sqrt{(-21)^{2} -4(5)(-39)} }{2(5)}\\ x_{1,2}=\frac{21(+-)\sqrt{441+780} }{10}=\frac{21(+-35)}{10}\\x_{1}=\frac{21+35}{10}=\frac{56}{10} \approx 5.6\\ x_{2}=\frac{21-35}{10}=\frac{-14}{10} \approx -1.4$

Therefore, the x-interecepts are 5.6 and -1.4, approximately.

7 0

3 years ago