Page 343 - Artificial Intellegence_v2.0_Class_11
P. 343
9. A survey was conducted to study student satisfaction regarding online classes. Students were asked questions
like "How many hours did you spend online?" and "On a scale from 1 to 10 how satisfied are you with your online
classes?". The scatterplot and the regression line from this survey are given below.
10
8
6
4
2
0
5 10 15 20
Interpret the slope of the regression line in the context of the survey.
Ans. We first need to evaluate the slope of the regression line. To find the slope, we find two points whose coordinates
can be determined easily. From the graph, we see that the line goes through the points (10,6) and (15,4). The slope
of the regression line can now be found using the formula:
rise 4 – 6 –2
Slope = run = 15 – 10 = 5
The rise is the change in y and y represents online class satisfaction rating. Since the slope is negative, the numerator
indicates a decrease in satisfaction. Thus, the numerator represents a decrease in satisfaction of 2 on the scale from
1 to 10. The run is the change in x and x represents the online class hours. Thus, the denominator represents an
increase of 5 hours of class time.
Now, put this all together and interpret the slope as telling us that for every additional 5 hours of online class that
students are asked to join/study, their satisfaction goes down an average of 2 points.
10. Identify the skewness of the following histograms:
a.
80
70
60
No. of students 40
50
30
20
10
0
0 1 1.2 1.4 1.6 1.8 2
Heights (in m)
Practical Questions 341

