A+ Answers

1. If samples of size n=25 are selected from the population of the heights of male youngsters who are normally distributed with a mean of 60 inches and a standard deviation of 10, what percentage of the sample means would you expect to be

a) between 57 and 63?

b) less than 58?

c) 61 or larger?

2. The resting heart rates were measured in a sample of women smokers and nonsmokers at ChicagoStateUniversity. There were 14 smokers and 18 non smokers in the sample. Was there a significant difference in the resting heart rates of the two groups? (use alpha = 0.05 and a two-tailed test)

Smokers                                  Nonsmokers
78          90                  72        62
100        85                  82        66
88          82                  62        68
62          77                  84        96
94          91                  91        58
88          90                  68        87
76          68                  72        80

                                    64        78
                                    76        69

4. Use the following BMI data scores, 25 27 31 33 26 28 38 41 24 32 35 40. How many subjects would be needed to ensure that a 95% confidence interval estimate of BMI had a margin of error not exceeding 2 units?

5. The mean BMI in patients free of diabetes was reported as 28.2. The investigator conducting the study described in using the BMI data scores above hypothesizes that the BMI in patients free of diabetes is higher. Based on the BMI data scores above is there evidence that the BMI is significantly higher than 28.2? Use 5% level of significance.

6. Do the experimental conditions cause a change in the systolic blood pressure of females? Use alpha=0.05

Case      Before  After     D            D^2

16-F      105       103        2             4

17-F      118       120        -2            4

18-F      97         95          2             4

19-F      104       105        -1            1

20-F      99         104        -5            25

21-F      131       134        -3            9

22-F      108       105        3             9

23-F      112       110        2             4

24-F      97         100        -3            9

25-F      104       107        -3            9

26-F      103       100        3             9

27-F      114       112        2             4

28-F      96         98          -2            4

29-F      126       127        -1            1

30-F      109       106        3             9

                           Total    -3            105