Page 2 QUESTION ONE Every 4 months contractors are tested to see if their time in minutes to assemble a particular component have changed. The times taken to assemble the component are normally distributed. A random sample of 8 contractors was chosen and their times to assemble the component are recorded in March and in July. The data are given in the table below Contractor A March B C D E F G H 17 19 22 26 15 28 18 21 July 19 18 25 24 17 25 16 19 a. Define the terms: i. Confidence interval [2 marks] ii. Type I and Type II errors. [2 marks] b. Calculate a 95% confidence interval for the mean difference in time. [5 marks] c. Comment on the hypothesis that the two mean times for the two groups are equal. Use the 5% level of significance. [6 marks] QUESTION TWO A researcher is interested in finding out the impact of study hours on students' GPA. The following table shows the number of hours a student studies per day and the corresponding GPA of the student. Student 1 GPA Study hours 2.8 5 2 3.4 7 3 3.6 9 4 2.1 3 5 4.0 8 6 3.1 4 a. What does a scatterplot represent? [2 marks] b. Estimate a simple linear regression model and find the value of the parameters. [6 marks] c. Interpret the intercept and the slope coefficients [2 marks] d. Compute the correlation coefficient and the coefficient of determination. Interpret the coefficient of determination [5 marks]

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.6: Summarizing Categorical Data
Problem 10CYU
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Answer the attachment below alongside with the breakdown of the answers.
Page 2
QUESTION ONE
Every 4 months contractors are tested to see if their time in minutes to assemble a particular component
have changed. The times taken to assemble the component are normally distributed. A random sample
of 8 contractors was chosen and their times to assemble the component are recorded in March and in
July. The data are given in the table below
Contractor A
March
B
C
D
E
F
G
H
17
19
22
26
15
28
18
21
July
19
18
25
24
17
25
16
19
a. Define the terms:
i.
Confidence interval [2 marks]
ii.
Type I and Type II errors. [2 marks]
b. Calculate a 95% confidence interval for the mean difference in time. [5 marks]
c. Comment on the hypothesis that the two mean times for the two groups are equal. Use the 5%
level of significance. [6 marks]
QUESTION TWO
A researcher is interested in finding out the impact of study hours on students' GPA. The following table
shows the number of hours a student studies per day and the corresponding GPA of the student.
Student
1
GPA
Study hours
2.8
5
2
3.4
7
3
3.6
9
4
2.1
3
5
4.0
8
6
3.1
4
a. What does a scatterplot represent? [2 marks]
b. Estimate a simple linear regression model and find the value of the parameters. [6 marks]
c. Interpret the intercept and the slope coefficients [2 marks]
d. Compute the correlation coefficient and the coefficient of determination. Interpret the coefficient
of determination [5 marks]
Transcribed Image Text:Page 2 QUESTION ONE Every 4 months contractors are tested to see if their time in minutes to assemble a particular component have changed. The times taken to assemble the component are normally distributed. A random sample of 8 contractors was chosen and their times to assemble the component are recorded in March and in July. The data are given in the table below Contractor A March B C D E F G H 17 19 22 26 15 28 18 21 July 19 18 25 24 17 25 16 19 a. Define the terms: i. Confidence interval [2 marks] ii. Type I and Type II errors. [2 marks] b. Calculate a 95% confidence interval for the mean difference in time. [5 marks] c. Comment on the hypothesis that the two mean times for the two groups are equal. Use the 5% level of significance. [6 marks] QUESTION TWO A researcher is interested in finding out the impact of study hours on students' GPA. The following table shows the number of hours a student studies per day and the corresponding GPA of the student. Student 1 GPA Study hours 2.8 5 2 3.4 7 3 3.6 9 4 2.1 3 5 4.0 8 6 3.1 4 a. What does a scatterplot represent? [2 marks] b. Estimate a simple linear regression model and find the value of the parameters. [6 marks] c. Interpret the intercept and the slope coefficients [2 marks] d. Compute the correlation coefficient and the coefficient of determination. Interpret the coefficient of determination [5 marks]
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