Question

A manufacturer of cases for sound equipment requires drilling holes for metal screws. The drill bits wear out and must be replaced; there is expense not only in the cost of the bits but also for lost production. Engineers varied the rotation speed of the drill and measured the life- time y of four bits at each of five speeds.
Speed Lifetime
60 4.6
60 3.8
60 4.9
60 4.5
80 4.7
80 5.8
80 5.5
80 5.4
100 5
100 4.5
100 3.2
100 4.8
120 4.1
120 4.5
120 4
120 3.8
140 3.6
140 3
140 3.5
140 3.4
1. Create a scatterplot of the data. Does there appear to be a relation? Does it appear to be linear?
2. Regardless fit a simple linear regression model to the data. What can you say about the fit of the model to the data?
3. Is there any evident outlier 
. Remove this observation and fit the regression model again. Is it improving the model f?

Answer 1

Answer:

There seems to be m linear relation between te data.

Negative relationships between variables.

Step-by-step explanation:

Speed(X)

60

60

60

60

80

80

80

80

100

100

100

100

120

120

120

120

140

140

140

140

Lifetime (Y) :

4.6

3.8

4.9

4.5

4.7

5.8

5.5

5.4

5

4.5

3.2

4.8

4.1

4.5

4

3.8

3.6

3

3.5

3.4

The linear regression equation obtained by fitting the data using a regression model is :

ŷ = -0.017X + 6.03

From the regression plot, the relationship between the two variables, speed and lifetime is negative, that is an increase in one variable will lead to a corresponding decrease in the other.