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iren2701 [21]
3 years ago
11

Fifty randomly selected individuals were timed completing a tax form. the sample mean was 23.6 minutes; the sample standard devi

ation was 2.4 minutes. a 99% confidence interval for the mean time required by all individuals to complete the form is about:
Mathematics
1 answer:
VLD [36.1K]3 years ago
5 0
Given:
n = 50, sample size
\bar{x} = 23.6 \, min, sample mean
s = 2.4 min, sample standard deviation.

The confidence interval is
\bar{x} \pm t^{*} \frac{s}{ \sqrt{n} }

At the 99% confidence level, t* (from the student's t-distribution) is 
t* = 2.68
Therefore
t*(s/√n) = 2.68*(2.4/√50) = 0.9096

The confidence interval is
(23.6-0.9096, 23.6+0.9096) ≈ (22.69, 24.51)

Answer: (22.7, 24.5)

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Let X represent the SAT score of an entering freshman at University X. The random variable X is shown to have a N(1200, 90) dist
Lelechka [254]
The correct answer to this question is 0.1456. This is <span>the probability that X bar will be greater than Y bar. </span>Probability is the measure of how likely an event is. The formula is the ratio of the number of favorable outcomes to the total number of possible outcomes. Thank you for posting your question. I hope that this answer helped you. Let me know if you need more help. 
4 0
3 years ago
3.5x + 6.5y= 1800 <br><br> WRITE IN SLOPE INTERCEPT FORM!<br> show all work
Zigmanuir [339]
3.5x + 6.5y = 1800
Move 3.5x to another side.
6.5y = -3.5x +1800
Divide by 6.5.
y = -3.5/6.5x + 1800
If we round it would be:
Y = 0.5x + 1800
0.5x is the slope and 1800 is the y-intercept.
Hope that helps.
6 0
2 years ago
Find the difference between and 8/15 - -(2/3). Show all calculations in your final answer please!! :)
sasho [114]

Answer:

\boxed{\dfrac{34}{15}}

Step-by-step explanation:

\text{Use }\LaTeX (ノ◕ヮ◕)ノ*:・゚✧

\dfrac{8}{5} - - \left(\dfrac{2}{3}\right)

\dfrac{8}{5} - \left[-\dfrac{2}{3}\right]

\dfrac{8}{5} +\dfrac{2}{3}

\dfrac{8(3)}{5(3)} +\dfrac{2(5)}{3(5)}

\dfrac{24}{15} +\dfrac{10}{15}

\boxed{\dfrac{34}{15}}

3 0
3 years ago
Read 2 more answers
According to a Pew Research Center, in May 2011, 35% of all American adults had a smart phone (one which the user can use to rea
Veronika [31]

Answer:

p_v =P(z>1.82)=0.034  

Assuming a standard significance level of \alpha=0.05 the best conclusion for this case would be:

4. There is not enough evidence to show that more than 35% of community college students own a smart phone (P-value = 0.034).

Because p_v

If we select a significance level lower than 0.034 then the conclusion would change.

Step-by-step explanation:

Data given

n=300 represent the random sample taken

X=120 represent the people who have a smart phone

\hat p=\frac{120}{300}=0.4 estimated proportion of people who have a smart phone

p_o=0.35 is the value that we want to test

z would represent the statistic (variable of interest)

p_v represent the p value (variable of interest)  

System of hypothesis

We need to conduct a hypothesis in order to test the claim that the true proportion of people who have a smart phone is higher than 0.35, the system of hypothesis are.:  

Null hypothesis:p\leq 0.35  

Alternative hypothesis:p > 0.35  

The statistic is given by:

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

Calculate the statistic  

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

z=\frac{0.4 -0.35}{\sqrt{\frac{0.35(1-0.35)}{300}}}=1.82  

Statistical decision  

Since is a right tailed test the p value would be:  

p_v =P(z>1.82)=0.034  

Assuming a standard significance level of \alpha=0.05 the best conclusion for this case would be:

4. There is not enough evidence to show that more than 35% of community college students own a smart phone (P-value = 0.034).

Because p_v

If we select a significance level lower than 0.034 then the conclusion would change.

4 0
3 years ago
(14x-13) (4x+13) (6x+2)
Diano4ka-milaya [45]

Answer:

x = 7.416666667

Set everything equal to 180 (the total # of degrees in a triangle)

180 = 14x-13 + 4x+13 + 6x+2

Combine the variables

180 = 24x - 13 + 13 + 2

Do the math

180 = 24x +2

178 = 24x

x = 7.416666667

3 0
2 years ago
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