# Project #22247 - Biostatistics

Question 1.) An investigator hypothesizes that cholesterol levels in children might be affected by educating their parents on proper nutrition and exercise.  A sample of 40 families with a child between the ages of 10 to15 who has been diagnosed with high cholesterol agree to participate in the study.  All parents are provided educational information on nutrition and exercise.  After following the prescribed program, their child's total mean cholesterol level is measured.  The children's mean cholesterol level is 175 with a standard deviation of 19.5. Is there significant evidence of a reduction in total cholesterol in the children? Run the appropriate test at the 5% level of significance and assume that the null value for total cholesterol is 191.

Question 2.) Suppose more detail is recorded in the primary outcome in the clinical trial described in Problem 10. The data are shown in Table 7-57. Is there a difference in the change in symptoms by treatment group? Run the appropriate test at a 5% level of significance.

Table 7-57
Treatment               Much Worse     Worse    No Change    Better    Much Better

Experimental               10                  17            35             28            10

Placebo                       12                  25             42            12           9

Question 3.)  Suppose a secondary outcome is recorded in the trial described in Problem 10 reflecting asthma severity on a scale of 0 to 100, with higher scores indicating more sever symptoms.  In the participants who receive the experimental medication, the mean symptom score is 74 with a standard deviation of 5.6, and in the placebo group, the mean symptom score is 85 with a standard deviation 6.0.  Is there a significant difference in mean symptom scores between groups? Run the appropriate test at a 5% level of significance.

Question 4.) Suppose a hypertension trial is mounted and 18 participants are randomly assigned to one of three comparison treatments.  Each participant takes the assigned medication and their systolic blood pressure is recorded after 6 months on the assigned treatment.  The data are shown in Table 7-58.  Is there a difference in mean systolic blood pressure among treatments? Run the appropriate test at alpha= 0.05

Table 7-58
Standard treatment                                                    Placebo                                              New Treatment
124                                                                               134                                                         114
111                                                                                143                                                        117
133                                                                                148                                                         121
125                                                                                142                                                          124
128                                                                                150                                                          122
115                                                                                 160                                                          128

Question 5.) Suppose the results of the analyses in Problem 15 through 17 are reported and criticized because the participants were not randomized to different diets, and that there may be other factors associated with change in cholesterol.  A third study run to estimate the effect of the low-carbohydrate diet on cholesterol levels.  In the third study, participants cholesterol levels are measured before starting the program and then after 6 months on the program. The data are shown below:

Before Program     210           230            190       215      260       200
After 6 months       215           240             190      200      280       210
Is there a significant increase in cholesterol after 6 months on the low-carbohydrate diet? Run the appropriate test at a 5% level of significance.

Question 6.) A study is conducted to compare three new appetite suppressants (A,B, and C) to a placebo in terms of their effects on weight reduction.  A total of 80 participants are involved and are randomly assigned to the comparison groups in equal numbers.  The outcome of interest is weight reduction, measured in pounds.  The data shown in Table7-61 are observed after 3 months on treatment.  Is there a significant difference in mean weight reduction among the four treatments? Use as 5% level of significance. (Hint: SST = 1889.)

Table 7-61
Mean (SD)                   A                         B                         C                             Placebo
weight reduction         6.4 (4.1)             8.9 (4.0)               2.2 (3.9)                    2.5 (4.3)

Please show all calculations so I can understand and show my work.  Look forward to hearing back from you

 Subject Mathematics Due By (Pacific Time) 02/06/2014 11:59 pm
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