Predicting number of patient smokers by MA 250 Statistics Columbia College Fall 2018

Predicting number of patient
smokers
by
MA 250 Statistics
Columbia College
Fall 2018
1. How many data items were in your data set?

Answer
There are 32 data items. This is based on the count
2. Determine the Mean
Answer
Mean=∑xi
n =15.7+13.2+22.6+...+13.1+20.7+15.5
32 =474.7
32 =14.83438
3. Determine the Median
Answer
Median=16 th value+17 thvalue
2 =14.6+14.7
2 =29.3
2 =14.65
4. Determine the Mode (if one exists)
Answer
Mode = the most frequent value
Mode=7
5. Sort the data and draw a labeled scatterplot of the data
Answer
6. Determine the equation of the line of best fit of the sorted data and draw its graph on
the data set (#5 & #6 should be on the same graph)

Answer
The line of the best fit is obtained as follows;
y=7.42+0.4494 x
7. Determine the correlation coefficient
Answer
The correlation coefficient is given as;
R=√R2=√0.9666=0.9832
8. How good a fit is the regression line to the actual data?
Answer
Since the coefficient of determination is 0.9666; this implies that 96.66% of the variation
in the dependent variable (number of patients who quit smoking) is explained by the year
(independent variable). Thus we can conclude that the regression line is very good in
fitting the actual data.
9. Interpret the meaning of the slope of the regression line or explain why it has no
meaning.