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denis-greek [22]

4 years ago

15

Carlene is selling t-shirts for a fundraiser. the t-shirts cost $20 each. to date, she has raised $800. her goal is to raise mor

e than $9,600. how many more t-shirts, x, does carlene need to sell to reach her goal?

1 answer:

GarryVolchara [31]4 years ago

3 0

She needs to sell 440 or more t-shirts.

You might be interested in

Suppose we are testing people to see if the rate of use of seat belts has changed from a previous value of 88%. Suppose that in

Andreas93 [3]

Answer:

a) We would expect to see 500*0.88=440

b) $z=\frac{0.9 -0.88}{\sqrt{\frac{0.88(1-0.88)}{500}}}=1.376$

$p_v =2*P(Z>1.376)=0.167$

So the p value obtained was a very high value and using the significance level assumed $\alpha=0.05$ 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 true proportion is not significant different from 0.9.

The p value is a criterion to decide if we reject or not the null hypothesis, when $p_v$ we reject the null hypothesis in other case we FAIL to reject the null hypothesis. And represent the "probability of obtaining the observed results of a test, assuming that the null hypothesis is correct".

Step-by-step explanation:

Data given and notation

n=500 represent the random sample taken

X=450 represent the people that have the seat belt fastened

$\hat p=\frac{450}{500}=0.9$ estimated proportion of people that have the seat belt fastened

$p_o=0.88$ is the value that we want to test

$\alpha$ represent the significance level

z would represent the statistic (variable of interest)

$p_v{/tex} represent the p value (variable of interest) Part aWe would expect to see 500*0.88=440Part bConcepts and formulas to use We need to conduct a hypothesis in order to test the claim that the true proportion changes fro m 0.88.: Null hypothesis:[tex]p=0.88$

Alternative hypothesis: $p \neq 0.88$

When we conduct a proportion test we need to use the z statisitc, and the is given by:

$z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}$ (1)

The One-Sample Proportion Test is used to assess whether a population proportion $\hat p$ is significantly different from a hypothesized value $p_o$ .

Calculate the statistic

Since we have all the info requires we can replace in formula (1) like this:

$z=\frac{0.9 -0.88}{\sqrt{\frac{0.88(1-0.88)}{500}}}=1.376$

Statistical decision

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.

The significance level assumed is $\alpha=0.05$ . The next step would be calculate the p value for this test.

Since is a bilateral test the p value would be:

$p_v =2*P(Z>1.376)=0.167$

So the p value obtained was a very high value and using the significance level assumed $\alpha=0.05$ 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 true proportion is not significant different from 0.9.

The p value is a criterion to decide if we reject or not the null hypothesis, when $p_v$ we reject the null hypothesis in other case we FAIL to reject the null hypothesis. And represent the "probability of obtaining the observed results of a test, assuming that the null hypothesis is correct".

8 0

3 years ago

A powerful women's group has claimed that men and women differ in attitudes about sexual discrimination. A group of 50 men (grou

MA_775_DIABLO [31]

Answer:

the lower limit is 35% women believed and 65% of men believed in serial discrimination

6 0

3 years ago

Please help me expand theses and then help me factorise these brackets

melisa1 [442]

Answer:

-9xy+16x

Step-by-step explanation:

x(y-2) +3x(6-y) -7xy

Distribute

xy -2x +18x-3xy -7xy

Combine like terms

-9xy+16x

3 0

3 years ago

Read 2 more answers

Do any of them you know

snow_tiger [21]

Answer:

I believe I am correct.

1: slope

2: linear equation

3: y-intercept

4: slope-intercept form

5: y-intercept is (0,6) the slope is -2

6: y-intercept is (0,3.4) the slope is 10/6

7: y-intercept is (0,4) the slope is -4/16

Hope this works for you Jack Jiang.

5 0

3 years ago

For 300 trading days, the daily closing price of a stock (in $) is well modeled by a Normal model with mean $196.99 and stand

KATRIN_1 [288]

Answer:

a) 2.5% b) 84% c) 95% d) D. The more unusual day is if the stock closed below $185 because it has the largest absolute z-score.

Step-by-step explanation:

For a) b) and c) we will use the empirical rule, so, we can observe the image shown below

a) 211.23 is exactly two standard deviation above the mean, so, the probability that on a randomly selected day in this period the stock price closed above 211.23 is 2.35% + 0.15% = 2.5%

b) 204.11 represents exactly one standard deviation above the mean, so, the probability of being below 204.11 is 50% + 34% = 84%

c) The probability of getting a value between 182.75 and 211.23 is 95%, this because 182.75 is exactly two standard deviations below the mean and 211.23 is exactly two standard deviations above the mean.

d) The z-score related to 208 is $z_{1}$ = (208-196.99)/7.12 = 1.5 and the z-score related to 185 is $z_{2}$ = (185-196.99)/7.12 = -1.7, therefore, the more unusual day is if the stock closed below $185 because it has the largest absolute z-score.

5 0

3 years ago