Assignment 12

Due in class on Monday, April 17.

Reading

Sections 7.1 and 7.2 of Chapter 7.

Graded Problems

1.

7.8

2.

7.60. Do parts (a), (b) and (c) and add the following part (d).

(d) Comment on the design of this study. How could it have been improved? Suggest a design for a randomized controlled experiment that would have better addressed the effectiveness of the weight loss program.

3.

7.62

4.

7.65

5.

7.66. Do parts (a), (b) and (c) and add the following part (d).

(d) Calculate a p-value for the test in part (c) (with Table C you may only be able to report bounds on your p-value). Interpret the p-value in the context of the problem: how strong is the evidence on whether the mean potency is equal to the standard release potency?

Additional Ungraded Problems

1.

Problem 7.9

2.

Problem 7.10

3.

Problem 7.68

4.

Problem 7.71

For 7.9 and 7.10 you might find the computer output on the following page helpful.

> right <- c(113,105,130,101,138,118,87,116,75,96,122,103,116
+ ,107,118,103,111,104,111,89,78,100,89,85,88)
> left <- c(137,105,133,108,115,170,103,145,78,107,84,148,147,
+ 87,166,146,123,135,112,93,76,116,78,101,123)
> right
 [1] 113 105 130 101 138 118  87 116  75  96 122 103 116 107 118 103 111 104 111
[20]  89  78 100  89  85  88
> left
 [1] 137 105 133 108 115 170 103 145  78 107  84 148 147  87 166 146 123 135 112
[20]  93  76 116  78 101 123


> mean(right)
[1] 104.12
> mean(left)
[1] 117.44
> sd(right)
[1] 15.79641
> sd(left)
[1] 27.26273


> diff <- right-left
> diff
 [1] -24   0  -3  -7  23 -52 -16 -29  -3 -11  38 -45 -31  20 -48 -43 -12 -31  -1
[20]  -4   2 -16  11 -16 -35


> mean(diff)
[1] -13.32
> sd(diff)
[1] 22.936