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2 years ago

Please help !!!!:!:):):$:)

Mathematics

2 answers:

IRISSAK [1]2 years ago

6 0

The correct answer is B

djverab [1.8K]2 years ago

4 0

Answer: B. 9(−7+10x^2)

Step-by-step explanation: 9(−7+10x^2)

=(9)(−7+10x^2)

=(9)(−7)+(9)(10x^2)

=−63+90x^2

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The National Center for Education Statistics surveyed a random sample of 4400 college graduates about the lengths of time requir

Paha777 [63]

Answer:

95% confidence interval for the mean time required to earn a bachelor’s degree by all college students is [5.10 years , 5.20 years].

Step-by-step explanation:

We are given that the National Center for Education Statistics surveyed a random sample of 4400 college graduates about the lengths of time required to earn their bachelor’s degrees. The mean was 5.15 years and the standard deviation was 1.68 years respectively.

Firstly, the pivotal quantity for 95% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample mean time = 5.15 years

$\sigma$ = sample standard deviation = 1.68 years

n = sample of college graduates = 4400

$\mu$ = population mean time

Here for constructing 95% confidence interval we have used One-sample z test statistics although we are given sample standard deviation because the sample size is very large so at large sample values t distribution also follows normal.

So, 95% confidence interval for the population mean, $\mu$ is ;

P(-1.96 < N(0,1) < 1.96) = 0.95 {As the critical value of z at 2.5%

level of significance are -1.96 & 1.96}

P(-1.96 < $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ < 1.96) = 0.95

P( $-1.96 \times {\frac{\sigma}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $1.96 \times {\frac{\sigma}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-1.96 \times {\frac{\sigma}{\sqrt{n} } }$ < $\mu$ < $\bar X+1.96 \times {\frac{\sigma}{\sqrt{n} } }$ ) = 0.95

95% confidence interval for $\mu$ = [ $\bar X-1.96 \times {\frac{\sigma}{\sqrt{n} } }$ , $\bar X+1.96 \times {\frac{\sigma}{\sqrt{n} } }$ ]

= [ $5.15-1.96 \times {\frac{1.68}{\sqrt{4400} } }$ , $5.15+1.96 \times {\frac{1.68}{\sqrt{4400} } }$ ]

= [5.10 , 5.20]

Therefore, 95% confidence interval for the mean time required to earn a bachelor’s degree by all college students is [5.10 years , 5.20 years].

8 0

3 years ago

Maya wants to know how many games the seventh grade students at her school play on their phones. Which is the BEST population fo

FrozenT [24]

Answer:

The best population for Maya's school would be all the seventh grade students at Maya's school, because that is who she wants to know how many games they play.

D. All the seventh grade students at Maya's school.

Hope this helps ;)

4 0

3 years ago

Read 2 more answers

Help please it’s scatter plots

gogolik [260]

I can’t see the picture

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2 years ago

draw a new location of the pole barn on the graph below. Note that the stock tank is located at the origin.

krok68 [10]

Answer:

i think you reflect across the axis

Step-by-step explanation:

i learned this

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6 0

3 years ago

if their is a family of 9 and their are 4 boys and 5 girls what is the percentage percentage of both male and female

gregori [183]

Boys 4/9 = 44.44% Girls 5/9 = 55.55%

Fraction to percentage: Divide the top by the bottom then multiply the result by 100

6 0

3 years ago