Worksheet # 5 Solutions (40 Pts)
Name:______Recitation Section:______
An important characteristic of newborn infants is their birth weight. Babies with low birth weights tend to have significantly more developmental problems later on in life than those who are born heavier. A new pre-natal vitamin supplement has been developed that is supposed to address this issue. Specifically, it is supposed to aid the fetus in developing more body mass. A SRS of weights from 12 newborns was collected. The data follow in Table 1. The descriptive statistics follow also in Output 1. At a significance level of 0.025, is there enough evidence to conclude that the average birth weights of this group is greater than the 3.25 kg birth weight normally associated with newborn infants?
1) Ho: m 3.25 [2 pt]
Ha: m > 3.25 [2 pt]
2) a = 0.025 [1 pt]; df = 11 [1 pt]; t-crit = 2.201 [3 pt]
3 & 5) The decision graphic: [6 pt]
4) t-calc = 2.97 [3 pt]
6) The statistical decision is: [2 pt]
Reject ho
7) The English interpretation is: [5 pt]
At a significance level of 0.025, the evidence suggests that babies treated with the pre-natal vitamin supplement have higher birth weights than the general average.
Use the information in the following setting to answer questions 8 – 11:
In order to promote some protective legislation an environmental group sets up equipment to collect rain samples and measure their sulfate (S04) levels. If the average S04 level in the rainfall is more than 12 kg/HA the group will attempt to influence the legislature to pass more stringent environmental laws. A SRS of 20 rain samples was collected and the minitab output for the hypothesis test is reported in Output 2:
8) Ho: m 12 [2 pt]
Ha: m > 12 [2 pt]
9) The P-Value is: 0.81 [2 pt]
10) The statistical decision is: [3 pt]
FTR Ho
11) The English interpretation is: [6 pt]
Since the P-value is so big (0.81) we cannot conclude that the average S04 levels in the rainfall is more than 12 kg/Ha
Rick Gumina STCC201 Worksheet5_Sol_F04.doc
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