In: Statistics and Probability
In a study conducted to investigate browsing activity by shoppers, each shopper was initially classified as a nonbrowser, light browser, or heavy browser. For each shopper, the study obtained a measure to determine how comfortable the shopper was in a store. Higher scores indicated greater comfort. Suppose the following data were collected.
Light | Heavy | |||
Nonbrowser | Browser | Browser | ||
6 | 5 | 10 | ||
7 | 6 | 12 | ||
8 | 5 | 10 | ||
5 | 4 | 12 | ||
5 | 7 | 9 | ||
6 | 4 | 11 | ||
7 | 6 | 10 | ||
6 | 5 | 12 |
a. Use to test for a difference among mean comfort scores for the three types of browsers.
Compute the values identified below (to 2 decimals, if necessary).
Sum of Squares, Treatment | |
Sum of Squares, Error | |
Mean Squares, Treatment | |
Mean Squares, Error |
Calculate the value of the test statistic (to 2 decimals, if necessary).
H0: Null Hypothesis: (There is no difference among mean comfort scores for the three types of browsers)
HA: Alernative Hypothesis: (At least one mean is different from other 2 means) (There is a difference among mean comfort scores for the three types of browsers) (Claim)
From the given data, the following Table is calculated:
Nonbrowser | Light Browser | Heavy Browser | Total | |
N | 8 | 8 | 8 | 24 |
50 | 42 | 86 | 178 | |
Mean | 6.25 | 5.25 | 10.75 | 7.417 |
320 | 228 | 934 | 1482 | |
Std. Dev. | 1.0351 | 1.0351 | 1.165 | 2.6526 |
From the above Table, ANOVA Table is calculated as follows:
Source of Variation | Sum of Squares | Degrees of Freedom | Mean Square | F Stat |
Treatments | 137.3333 | 2 | 137.3333/2=68.6667 | 68.6667/1.1667=58.86 |
Error | 24.5 | 21 | 24.5/21=1.1667 | |
Total | 161.8333 | 23 |
F Stat = 68.6667/1.1667=58.86
By Technology, P Value= 0.0000
Since P - value is less than , the difference is significant. Reject null hypothesis.
Conclusion:
The data support the claim that there is a difference among mean
comfort scores for the three types of browsers.
Answers to Questions asked:
Sum of squares, Treatment | 137.3333 |
Sum of squares, Error | 24.5 |
Mean square, Treatment | 68.6667 |
Mean square, Error | 1.1667 |
The value of the test statistic = 58.86