Question

Maintaining a healthy weight is important for women’s health. Some physicians recommend being back to your pre-pregnancy weight six months after giving birth. Public health officials are interested in whether this is a realistic goal. Do the women in North Carolina weigh more than their pre-pregnancy weight six months postpartum? In other words, is the six months post-pregnancy weight greater than their pre-pregnancy weight? Use a paired samples t-test to compare pst6wght (variable 1) and prewght (variable 2). This uses pst6wght-prewght. (12 points)

1. Set-up the hypotheses and significance level (2 points) 2. Set-up the decision rule (1 point) 3. Compute the test statistic using Excel (the test statistic is in your Excel output.) (5 points) 4. Give your conclusion. This must include either a comparison of the p-value to alpha or a comparison of the test statistic to the critical value. You also must explain what this result means. (4 points)

PREWGHT	PST6WGHT
180	195
204	195
135	140
107	130
144	144
120	125
139	135
187	190
158	185
200	204
127	124
134	132
210	201
110	115
192	191
163	165
148	149
105	115
217	218
182	195
111	115
222	203
159	161
217	203
157	149
123	125
206	201
116	119
206	193
220	201
148	145
123	124
160	167
203	201
168	154
117	123
197	186
191	195
223	225
166	189
171	201
223	225
111	141
105	107
150	152
107	137
114	129
146	148
150	149
217	204
207	220
198	192
99	124
131	166
125	142
169	168
163	164
154	157
128	143
174	191
219	198
100	106
118	124
184	175
113	113
181	185
136	145
187	184
180	181
189	191
205	205
224	201
215	216
111	119
124	121
156	186
124	128
199	195
158	165
155	158
153	152
214	215
173	185
209	211
162	165
176	165
159	162
166	154
118	118
149	157
151	196
101	102
182	189
155	163
119	121
107	108
196	194
203	201
115	128
144	149
126	154
115	121
147	156
205	210
160	160
225	252
139	137
153	139
184	181
182	185
111	124
182	191
144	145
127	127
170	174
123	136
119	125
221	229
195	201
211	242
204	235
98	105
136	135
144	142
160	168
183	181
156	159
99	125
126	130
107	117
225	190
221	210
123	136
140	146
140	141
134	137
123	141
222	204
222	221
194	195
171	172
108	125
113	124
103	118
98	113
115	131
134	154
167	171
131	135
214	249
188	187
212	213
203	205
113	133
203	201
101	104
182	181
119	121
99	119
176	210
134	136
198	195
137	138
105	108
147	156
146	147
219	215
176	208
114	119
209	210
125	158
147	148
177	178
168	186
115	116
101	111
147	157
113	121
112	125
179	185
124	125
120	126
185	195
126	146
136	145
206	208
212	204
124	145
148	154
101	106
207	204
185	199
121	143
146	152
163	178
208	203
137	145
136	139
153	175
175	165

Answer 1

Answer Date: 11/11/2019 To test the hypothesis is that the six months post-pregnancy weight is greater than their pre-pregnancy weight at 5% significance level. The null and alternative hypothesis is, HO:lla so Hilo > 0 The significance level is 5%. The t critical value at 5% significance level is, The sample size is small and right-tailed test. Look in the column headed a = 0.05 and the row headed in the t distribution table by using degree of freedom is,

d.f.=n-1 = 200 -1 = 199 The t critical value at 5% significance level is 1.653 . The decision rule is, Reject the null hypothesis, if the t-test statistics is greater than the t critical value is 1.653. The t-test statistics is, By using Excel software, find t-test statistics with the help of following steps: 1) Import the data. 2) Select t-test: Paired Two Samples for Means from Data Analysis in Data menu. Select Variable 1 Range and Variable 2 Range. 4) Give Hypothesized Mean Difference. 5) Select Labels and give Alpha. 3)

Choose Output Range from Output options. Click Ok. 7) t-Test: Paired Two Sample for Means PSTOWGHT 162.825 1242.868719 200 0.950549482 PREWGHT 157.475 1439.074749 200 Mean Variance Observations Pearson Correlation Hypothesized Mean Difference df t Stat P(T<=t) one-tail t Critical one-tail P(T<=t) two-tail t Critical two-tail 199 6.406961097 5.25456E-10 1.652546747 1.05091E-09 1.971956498 From the Excel output, the t-test statistics is 6.407)

4) Decision The statistical decision is that the t-test statistics which is 6.407 is higher than t-critical value which is 1.653, so the null hypothesis is rejected at 5% level of significance. There is sufficient evidence to indicate that the six months post-pregnancy weight is greater than their pre-pregnancy weight. The result is statistically significant.