Lab Project
Problem 1
Of the last ten times you've dropped your toast, it landed sticky-side down nine times. If these are a random sample from the $\text{Ber}(p)$ distribution, find an 80% confidence interval for $p$, the probability of the stidy side landing down. (Use `binconf()`
Problem 2
For the `Melanoma` (**MASS**) data set, use `prop.test()` to find a 99% confidence interval for the difference in proportion of male and female patients with an ulcer.
Problem 3
The `tud.recs` (**UsingR**) data set contains a sample of math SAT scores from some population in the variable `sat.m`. Find a 90% confidence interval for the mean math SAT score for this data. (Do not use `t.test(); find this confidence interval "by hand".)
Problem 4
In determining the recommended dosage of AZT for AIDS patients, tests were done comparing efficacy for various dosages. If a low dosage is effective, then that would be recommended, as it would be less expensive and would have fewer potential side effects.
A test to decide whether a dosage of 1,200 mg is similar to one of 400 mg is performed on two random samples of AIDS patients. A numeric measurement of a patient's health is made, and the before-and-after differences are recorded after treatment:
| Treatment |
|
|
|
|
|
|
|
|
|
|
| 400 mg group |
7 |
0 |
8 |
1 |
10 |
12 |
2 |
9 |
5 |
2 |
| 1200 mg group |
2 |
1 |
5 |
1 |
5 |
7 |
-1 |
8 |
7 |
3 |
Find a 90% confidence interval for the differences of the means. What do you assume about the data?
Problem 5
The following data is from IQ tests for pairs of twins that were separated at birth. One twin was raised by the biological parents, the other by adoptive parents.
| Twin pair |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
| Foster |
80 |
88 |
75 |
113 |
95 |
82 |
97 |
94 |
132 |
108 |
| Biological |
90 |
91 |
79 |
97 |
97 |
82 |
87 |
94 |
131 |
115 |
Find a 90% confidence interval for the differences of mean. What do you assume about the data? In particular, are the two samples independent?