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2 years ago

Here is a summary of the Boston Marathon completion times for two years.

Mathematics

2 answers:

artcher [175]2 years ago

7 0

Answer:

"It's approximately normal, because both sample sizes are at least 30."

Step-by-step explanation:

The shape of the population distribution is unknown; however as the sample size is 35 (fulfills the sample size criteria: $\geq$ 30), we can conclude that the sampling distribution is therefore approximately normal.

kondor19780726 [428]2 years ago

5 0

Answer:

Here is a summary of the Boston Marathon completion times for two years.

Year

Mean (minutes)

Standard deviation (minutes)

Number of runners

2012

263

21,576

31,984

2014

243

A sports journalist takes separate random samples of 35 runners from each year. Then they look at the

difference in the mean completion time sampled from each year 2012 - 2014).

What do we know about the shape of the sampling distribution of D2012 22014, and why?Step-by-step explanation:

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Answer:

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3 years ago

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3 years ago

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3 years ago

A college job placement office collected data about students’ GPAs and the salaries they earned in their first jobs after gradua

frez [133]

Answer:

X is the GPA

Y is the Salary

Standard deviation of X is 0.4

Standard deviation of Y is 8500

E(X)=2.9

E(Y)=47200

We are given that The correlation between the two variables was r = 0.72

a) $y = a+bx$

$b = \frac{\sum(x_i-\bar{x})(y_i-\bar{y})}{\sum(x_i-\bar{x})^2} = \frac{r \times \sqrt{var(X) \times Var(Y)}}{Var(X)} = \frac{0.72 \times \sqrt{0.4^2 \times 8500^2}}{0.4^2} = 15300$

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So, slope = 15300

Intercept = 2830

So, equation : $y = 2830+15300x$

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Observed salary = Residual + predicted = -1860+53320 = 51440

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2 years ago

Is for over two and 20/6 proportions

ad-work [718]

No they're not proportional, and it's four*.
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3 years ago

Read 2 more answers