ID	IQ
101	70
102	85
103	86
104	76
105	84
106	96
107	94
108	56
109	115
110	97
111	77
112	128
113	99
114	80
115	118
116	86
117	141
118	88
119	96
120	96
121	107
122	86
123	80
124	107
125	101
126	91
127	125
128	96
129	99
130	99
131	115
132	106
133	105
134	96
135	50
136	99
137	85
138	88
139	120
140	93
141	87
142	98
143	78
144	100
145	105
146	87
147	94
148	89
149	80
150	111
151	104
152	85
153	94
154	75
155	73
156	76
157	107
158	88
159	89
160	96
161	72
162	97
163	76
201	82
202	93
203	85
204	75
205	85
206	80
207	101
208	89
209	80
210	94
211	88
212	104
213	88
214	88
215	112
216	83
217	104
218	101
219	92
301	72
302	90
303	92
304	71
305	86
306	79
307	83
308	114
309	100
310	93
311	91
312	98
313	91
314	46
315	85
401	107
402	104
403	85
404	76
405	95
406	86
407	89
408	76
409	96
410	101
411	108
412	102
413	77
414	74
415	92
501	96
502	76
503	80
504	79
505	75
601	82
602	97
603	91
604	92
605	77
606	111
607	78

The data come from a study of lead exposure and IQ in children. IQ scores were measured on a sample of children living in a community near a source of lead. The IQ scores were age-standardized using established normal values for the US population. Such age-standardized scores have a mean of 100 and a standard deviation of 15 in the US population.

3.2. Calculate the sample mean and sample SD of IQ. How do they compare numerically to the US population values?

3.3. Test the null hypothesis that the mean IQ score in the community is equal to 100 using the 2-sided 1-sample t-test with a significance level of 0.05. State the value of the test statistic and whether or not you reject the null hypothesis at significance level 0.05.

3.4. Give the p-value for the test in the previous question. State the interpretation of the p-value.

3.5. Compute a 95% confidence interval for the mean IQ. Do the confidence interval and hypothesis test give results that agree or conflict with each other? Explain.

3.6. Repeat the hypothesis test and confidence interval using a significance level of 0.01 and a 99% confidence interval.