homework_14_ans - MTH 1210 Biostatistics Apr 2809 Homework...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
MTH 1210 Biostatistics Apr 28’09 Homework #14 ( Hypothesis Testing for the Difference between Two Population Means ) See the handouts # 15, 15a, 15b. Use the MS Excel program Hypothesis_Testing_for_ the_Difference_between_Two_Population_Means.xls. Solving the problems remember that what we hope or expect to be able to conclude as a result of the hypothesis testing usually should be placed in the alternative hypothesis H A . Formulate at first the alternative hypothesis H A and then the null hypothesis H 0 which should be complementary to H A . Then, choose the proper sheet and block of cells in the aforementioned Excel program that correspond to your hypotheses H 0 and H A and enter the data only in the data entry cells belonging to the B - column. In the problems below assume that unknown population variances are equal . 7.3.1 (pg. 244 of the textbook) Subjects in a certain study included a sample of 40 men who claimed to engage in a variety of sports activities (multisport). The mean Body Mass Index (BMI) for these men was 22.41 with a standard deviation of 1.27 . A sample of 24 male rugby players had a mean BMI of 27.75 with a standard deviation of 2.64 . Is this sufficient evidence for one to clam that, in general, rugby players have a higher BMI than the multisport men? Let α = 0.01. SAMPLE 1 Size n 1 = 24 The mean x mean_1 * = 27.7 5 ONE-sided test Std. deviation s 1 = 2.64 HYPOTHESES SAMPLE 2 Size n 2 = 40 H 0 : µ 1 – µ 2 0 Null hypothesis The mean x mean_2 * = 22.4 1 Std. deviation s 2 = 1.27 H A : µ 1 – µ 2 > 0 Alternative hypothesis Hypothesized value of (µ 1 – µ 2 ) 0 = 0 df = n 1 + n 2 – 2 = 62 Level of significance α = 0.01 t (1 – α) = 2.3880 1 <== critical value at the upper right tail of the curve f(t) s p 2 = [(n 1 – 1)s 1 2 + (n 2 – 1)s 2 2 ]/(n 1 + n 2 – 2) = 3.60006 Test statistic t * = [(x mean_1 * – x mean_2 * ) – (µ 1 – µ 2 ) 0 ]/(s p 2 /n 1 + s p 2 /n 2 ) 1/2 = 10.9001 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
REJECT H 0 BECAUSE t * = 10.9001 > 2.3880 1 = t (1 – α) {Students should follow their textbook pg. 235- and the Excel program Hypothesis_Testing_for_the_Difference_between_Two_Population_Means.xls, sheet 2, lowest block of cells} 7.3.7 (pg. 247 of the textbook) Cortisol level determinations were made on two samples of women at childbirth. Group 1 subjects underwent emergency cesarean section
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/24/2011 for the course MATH 3000 taught by Professor Kzaer during the Spring '05 term at St. Johns College MD.

Page1 / 6

homework_14_ans - MTH 1210 Biostatistics Apr 2809 Homework...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online