Question

7. Philip wants to take a speed-reading course, but his wife thinks that it is a waste of time. To convince her that the course will really change the way that he reads, Philip decides to conduct an informal study. He pols seven people, asking them to tell the number of pages they were able to read in an hour before and then after they took the course. The results he obtained are found in the following table. Construct and interpret a 95% confidence interval for the true mean increase in reading speeds for people who have taken the speed-reading course. Round your CI limits to 1 decimal place. Number of pages read in one hour

Before Course: 35 50 45 50 60 70 65

After Course : 50 60 80 70 85 100 90

Answer 1

Solution

use following R-code for 95% confidence interval

Before_course=c(35,50,45,50,60,70,65)

After_Course=c(50,60,80,70,85,100,90)

t.test(Before_course,After_Course, conf.level=0.95, paired=TRUE)

Paired t-test

data: Before_course and After_Course
t = -7.0391, df = 6, p-value = 0.0004109
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
-30.80272 -14.91156
sample estimates:
mean of the differences
-22.85714

#95% confidence interval (-30.8, -14.9)