Chapter 14 Assignment Name Key SOURCE: Hosmer, D.W., Lemeshow, S. and Sturdivant, R.X. (2013) Applied Logistic Regression: Third Edition. These data are copyrighted by John Wiley & Sons Inc. and must be acknowledged and used accordingly. Data were collected at Baystate Medical Center, Springfield, Massachusetts during 1986. Description of the Data: The goal of this study was to identify risk factors associated with giving birth to a low birth weight baby (weighing less than 2500 grams). Data were collected on 189 women, 59 of which had low birth weight babies and 130 of which had normal birth weight babies. Four variables which were thought to be of importance were age, weight of the subject at her last menstrual period, race, and the number of physician visits during the first trimester of pregnancy. (See the Excel File \"Chapter 14 Dataset\" to complete the questions below.) Variable Names: ID: Identification Code LOW: Low Birth Weight (0 = Birth Weight >= 2500g, 1 = Birth Weight < 2500g) AGE: Age of the Mother in Years LWT: Weight in Pounds at the Last Menstrual Period RACE: Race (1 = White, 2 = Black, 3 = Other) SMOKE: Smoking Status During Pregnancy (1 = Yes, 0 = No) PTL: History of Premature Labor (0 = None 1 = One, etc.) HT: History of Hypertension (1 = Yes, 0 = No) UI: Presence of Uterine Irritability (1 = Yes, 0 = No) FTV: Number of Physician Visits During the First Trimester (0 = None, 1 = One, 2 = Two, etc.) BWT: Birth Weight in Grams Research Question: Is there a relationship between low birth weight (LOW) and smoking status during pregnancy (SMOKE)? 1. What type of test will we perform? 2. Create a contingency table of the data. To do this, you'll have to count the number of subjects who meet each of the desired criteria (i.e. LOW = 0 and SMOKE = 0, LOW = 0 and SMOKE = 1, etc.) [*Hint: Try using the COUNTIFS function in Excel for easier counting.) LOW = 0 SMOKE = 0 SMOKE = 1 LOW = 1 Total Total 189 3. List the assumptions for this type of analysis. 4. Identify the null and alternative hypothesis. H0: H1: Now, let's perform our analysis. In the Excel file, click on Sheet 1 at the bottom of the screen. Insert your values from question 2 into the table. You'll notice the chi square test statistic, critical value, p-value, and effect sizes are calculated for you. (You're welcome .) 5. According to the analysis, what is the expected number of babies with low birth weight born to mothers who smoked during pregnancy? How does this value compare to the observed frequency? 6. Identify the Chi-square test statistic and p-value for testing the claim that there is no association between smoking and low birth weight. Calculate the degrees of freedom and input this value into Excel. Test statistic: p-value: Degrees of freedom: 7. Identify the effect size. What type of association is indicated by the effect size? Calculate the odds ratio of a mother who smokes during pregnancy giving birth to a low birth weight baby compared to a mother who does not smoke. Input this value into the Excel file to see the confidence interval of the ratio. 8. What is your calculated odds ratio? Odds Ratio: 9. How would you interpret the odds ratio? 10. Use APA style reporting to write up your results of this analysis. ID LOW 85 86 87 88 89 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 111 112 113 114 115 116 117 118 119 120 121 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 154 155 156 159 160 161 162 163 164 166 167 168 169 170 172 173 174 175 176 177 179 180 181 182 183 184 185 186 187 188 189 190 AGE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 LWT 19 33 20 21 18 21 22 17 29 26 19 19 22 30 18 18 15 25 20 28 32 31 36 28 25 28 17 29 26 17 17 24 35 25 25 29 19 27 31 33 21 19 23 21 18 18 32 19 24 22 22 23 22 30 19 16 21 30 20 17 17 23 24 28 26 20 24 28 20 22 22 31 23 16 16 18 25 32 20 23 22 32 30 20 23 17 19 23 36 22 24 21 19 25 16 29 RACE 182 155 105 108 107 124 118 103 123 113 95 150 95 107 100 100 98 118 120 120 121 100 202 120 120 167 122 150 168 113 113 90 121 155 125 140 138 124 215 109 185 189 130 160 90 90 132 132 115 85 120 128 130 95 115 110 110 153 103 119 119 119 110 140 133 169 115 250 141 158 112 150 115 112 135 229 140 134 121 190 131 170 110 127 123 120 105 130 175 125 133 134 235 95 135 135 SMOKE 2 3 1 1 1 3 1 3 1 1 3 3 3 3 1 1 2 1 3 1 3 1 1 3 3 1 1 1 2 2 2 1 2 1 2 1 1 1 1 1 2 1 2 1 1 1 1 3 1 3 1 3 1 1 3 3 3 3 3 3 3 3 3 1 3 3 3 3 1 2 1 3 3 2 1 2 1 1 2 1 1 1 3 3 3 3 3 1 1 1 1 3 1 1 1 1 PTL 0 0 1 1 1 0 0 0 1 1 0 0 0 0 1 1 0 1 0 1 0 0 0 0 0 0 1 0 1 0 0 1 1 0 0 1 1 1 1 1 1 0 0 0 1 1 0 0 0 1 0 0 1 1 0 0 1 0 0 0 0 0 0 0 1 0 0 1 0 0 1 1 1 0 1 0 0 1 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 1 1 0 HT 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 0 0 2 1 2 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 UI 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 FTV 1 0 0 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 BWT 0 3 1 2 0 0 1 1 1 0 0 1 0 2 0 0 0 3 0 1 2 3 1 0 2 0 0 2 0 1 1 1 1 1 0 2 2 0 2 1 2 2 1 0 0 0 4 0 2 0 1 0 0 2 0 0 0 0 0 0 0 2 0 0 0 1 2 6 1 2 0 2 1 0 0 0 1 4 0 0 1 0 0 0 0 0 0 0 0 1 0 2 0 0 0 1 2523 2551 2557 2594 2600 2622 2637 2637 2663 2665 2722 2733 2750 2750 2769 2769 2778 2782 2807 2821 2835 2835 2836 2863 2877 2877 2906 2920 2920 2920 2920 2948 2948 2977 2977 2977 2977 2992 3005 3033 3042 3062 3062 3062 3076 3076 3080 3090 3090 3090 3100 3104 3132 3147 3175 3175 3203 3203 3203 3225 3225 3232 3232 3234 3260 3274 3274 3303 3317 3317 3317 3321 3331 3374 3374 3402 3416 3430 3444 3459 3460 3473 3475 3487 3544 3572 3572 3586 3600 3614 3614 3629 3629 3637 3643 3651 191 192 193 195 196 197 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 4 10 11 13 15 16 17 18 19 20 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 40 42 43 44 45 46 47 49 50 51 52 54 56 57 59 60 61 62 63 65 67 68 69 71 75 76 77 78 79 81 82 83 84 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 29 19 19 30 24 19 24 23 20 25 30 22 18 16 32 18 29 33 20 28 14 28 25 16 20 26 21 22 25 31 35 19 24 45 28 29 34 25 25 27 23 24 24 21 32 19 25 16 25 20 21 24 21 20 25 19 19 26 24 17 20 22 27 20 17 25 20 18 18 20 21 26 31 15 23 20 24 15 23 30 22 17 23 17 26 20 26 14 28 14 23 17 21 154 147 147 137 110 184 110 110 120 241 112 169 120 170 186 120 130 117 170 134 135 130 120 95 158 160 115 129 130 120 170 120 116 123 120 130 187 105 85 150 97 128 132 165 105 91 115 130 92 150 200 155 103 125 89 102 112 117 138 130 120 130 130 80 110 105 109 148 110 121 100 96 102 110 187 122 105 115 120 142 130 120 110 120 154 105 190 101 95 100 94 142 130 1 1 1 1 1 1 3 1 3 2 1 1 1 2 1 3 1 1 1 3 1 3 1 3 1 3 1 1 1 1 1 1 1 1 3 1 2 3 3 3 3 2 3 1 1 1 3 3 1 1 2 1 3 3 3 1 1 1 1 3 2 1 2 3 1 3 3 3 2 1 3 3 1 1 2 2 2 3 3 1 1 1 1 2 3 3 1 3 1 3 3 2 1 0 1 1 0 0 1 0 0 0 0 0 0 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 0 0 0 0 0 0 1 1 1 0 0 1 1 0 1 0 0 0 0 1 1 0 1 1 1 0 1 1 0 0 0 1 1 0 0 1 0 1 1 1 0 0 1 1 1 1 0 0 0 1 1 1 0 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 1 0 0 0 1 0 0 0 2 0 0 0 0 0 1 0 0 2 0 0 1 0 1 0 1 0 0 0 1 0 0 1 1 1 0 1 0 0 0 0 0 0 1 0 0 1 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 1 0 1 0 0 0 0 1 0 0 0 0 1 0 0 1 0 0 1 0 0 1 0 1 1 1 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 1 0 0 1 0 2 4 2 1 2 1 0 1 0 0 2 1 1 0 1 0 2 2 1 0 1 1 0 2 0 0 0 0 1 1 0 1 0 0 0 1 0 2 2 0 0 0 1 2 0 0 0 0 3 1 0 0 0 1 0 0 0 0 4 0 1 0 1 0 0 0 0 0 1 3 0 2 1 3 0 0 2 2 0 0 3 3651 3651 3651 3699 3728 3756 3770 3770 3770 3790 3799 3827 3856 3860 3860 3884 3884 3912 3940 3941 3941 3969 3983 3997 3997 4054 4054 4111 4153 4167 4174 4238 4593 4990 709 1021 1135 1330 1474 1588 1588 1701 1729 1790 1818 1885 1893 1899 1928 1928 1928 1936 1970 2055 2055 2082 2084 2084 2100 2125 2126 2187 2187 2211 2225 2240 2240 2282 2296 2296 2301 2325 2353 2353 2367 2381 2381 2381 2395 2410 2410 2414 2424 2438 2442 2450 2466 2466 2466 2495 2495 2495 2495 Observed Values (O) LOW = 0 LOW = 1 Total 0 0 0 Chi Square Analysis 0 0 Pearson Chi-square #DIV/0! df Critical Value Err:502 SMOKE = 0 SMOKE = 1 Total Significance #DIV/0! Cramer's V #DIV/0! Odds Ratios Post Hoc Tests Confidence Intervals Err:502 Err:502 Expected Values (E) LOW = 0 Total #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! LOW = 0 SMOKE = 0 SMOKE = 1 Total LOW = 1 LOW = 1 Total #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! (O - E)^2/E SMOKE = 0 SMOKE = 1 Total