Question

BUS 272 - BUSINESS STATISTICS II PROJECT A company is testing the effectiveness of three new pills used to treat high blood pressure. 30 people with high blood pressure were selected. The 30 people were then divided into three groups of 10 each. Each person in a subgroup was given one of these pills. The number of points by which each person's blood pressure was reduced after one month of use is as follows: PILL A 15 21 17 16 14 16 14 21 17 15 PILL B 39 30 23 31 9 25 23 19 27 39 PILL C 29 12 15 18 21 15 12 21 18 29 Is there a significant difference in the ability of each of these drugs to reduce blood pressure? (Use a .05 level of significance.)

Answer 1

Null hypothesis H₀ : mean reduction in blood pressure for different pills are same

Alternative hypothesis H₁ : mean reduction in blood pressure for different pills are different

Now,

Using Excel, (Data -> Data Analysis -> Anova : Single Factor), we get the following output -

File Home Insert Page Layout Formulas Data Review View Help Tell me what you want A ZA From Access From Web From Other From Text Sources Get External Data Show Queries From Table New Query - La Recent Sources Get & Transform Existing Connections Connections Properties Refresh Edit Links Connections NG Sort Filt All- Sort & P17 B C D E ד G T Sum Count 10 10 166 265 Average Variance 16.6 6.488888889 26.5 81.61111111 19 37.77777778 LO 190 A 1 Anova: Single Factor 2 3 SUMMARY 4 Groups 5 Pill A 6 Pill B 7 Pillc 8 9 10 ANOVA 11 Source of Variation 12 Between Groups 13 Within Groups 14 15 Total df SS 533.4 MS F P-value Fcrit 2 266.7 6.356165593 0.005469129 3.354130829 27 41.95925926 1132.9 1666.3 29 16 17 18

The value of the test statistic F = 6.356

P-value = 0.0055

Since P-value < 0.05, so we fail to reject the null hypothesis and we can conclude that mean reduction in blood pressure for different pills are significantly different.