STAT 200-010代做、Python，c++程序代写代做、代写Java编程语言

日期：2020-10-31 10:38

Penn State University

STAT 200-010

Fall 2020

Second Midterm Exam

Thursday October 29th

, 2020 (8:25 AM – 10:20 AM)

Student Name:

ID:

Do not write anything in this table; this is for grader use only!

Question: 1

(a) (5 Pts.) What is meant by a scatter plot?

(b) (5 Pts.) Define the term “Time Plot”.

(c) (10 Pts.) Use Excel to calculate the correlation factor of the following data:

(d) (5 Pts.) Once you have calculated the correlation factor in “c” determine its “Direction”,

“Form”, and “Strength”.

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Question: 2

You are given the following data set:

X Y

1.2 3.6

2.4 7

3.1 9.5

4.5 13.8

5.6 17.2

This data set has a correlation factor 𝑟 = 0.9996. Do not use Excel in this question and show

your calculations in detail for full credit.

(b) (5 Pts.) Calculate the standard deviations 𝑆𝑥 = √.

(c) (5 Pts.) Calculate the slope 𝑏1 = 𝑟𝑆𝑦𝑆𝑥.

(d) (5 Pts.) Calculate the y-intercept 𝑏0 = 𝑦̅ − 𝑏1𝑥̅.

(e) (5 Pts.) Write down the linear regression equation 𝑦̂ = 𝑏0 + 𝑏1𝑥 (you need to substitute

numerical values for 𝑏0 and 𝑏1).

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Question: 3

You are presented with the following data set:

X Y 𝑦̂ Residuals

1 5.2

2 10.6

3 16.1

4 22.3

5 27.8

Do not use Excel for this question.

(a) (15 Pts.) Given that the linear-regression equation for the data set above is

𝑦̂ = 5.69𝑥 − 0.67, calculate 𝑦̂ (the predicted values of y according to the given

regression equation) and the residuals and fill them in the table above:

(b) (5 Pts.) Define “Extrapolation”.

(c) (5 Pts.) Use extrapolation to calculate 𝑦̂(7).

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Question: 4

A factory produces 3 different products, product A, product B, and product C. The table below

shows the total monthly cost (for 5 different months) sustained by the factory to produce a given

count of each product. Here are the data:

Month Total Factory

Cost (in $)

Product A Product B Product C

1 44439 515 541 711

2 43936 929 692 824

3 44464 800 710 758

4 41533 979 675 635

5 46343 1165 1147 901

(a) (20 pts.) Using Excel calculate the multiple-regression equation.

(b) (5 Pts.) Once you have derived that equation, use it predict the total cost sustained by the

factory to produce 300, 400, and 500 counts of the A, B, and C products, respectively.