1 A researcher conducted an experiment to determine the effe

1. A researcher conducted an experiment to determine the effect of the lecturer’s age on student preferences to hear her lecture. In a regular classroom situation, 30 students were told that the administration wished to know their preferences regarding a forthcoming visiting lecturer series. In particular, they were asked to evaluate a professor who “might be visiting the campus.” The professor was described to all students in the same way with one exception: One third of the students were told that the professor was 75 years old; one third were told the professor was 50 years old; and one third were told the professor was 25 years old. All students were then asked to indicate their willingness to attend the professor’s lecture (higher scores indicate greater willingness).

The following result were obtained: X1 X2 X3

(Scores of students told       (scores of students told        (scores of students told

Professor was 25 yrs. old )              professor was 50 yrs. old ) professor was 75 yrs. old )

65 63 67

38 42                                                       42

52                                                         60    77

71                                                         55                                                        32

69                                                         43                                                        52

72 36                                                        34

55                                                         69                                                        45

78                                                         57                                                        38

56                                                         67                                                        39

80                                                         79    46

Which statistical procedure would you apply to determine whether there is a significant difference between these groups of students with respect to their willingness to attend the lecture?

Solution

The mean of each data set and its standard deviation would be computed. Then certain confidence intervals would be computed for each data set.Certain confidence intervals are as under. It means that 99 % of the data lies within ± 2.58 of and so on.

99%

2.58

95%

1.96

90%

1.64

The confidence intervalsof the 3 data sets will determine whether there is a significant difference between these groups of students with respect to their willingness to attend the lecture.