A company claims that 9 out of 10 doctors (i.e., 90) recommend ...

[newyorker26]

A company claims that 9 out of 10 doctors (i.e., 90) recommend its brand of cough syrup to their patients.
 
  To test this claim against the alternative that the actual proportion is less than 90, a random sample of 100 doctors was chosen which resulted in 87 who indicate that they recommend this cough syrup. The test statistic in this problem is approximately:
  A) -0.50 B) -0.66 C) 1.00 D) -1.00

Question 2

State your conclusion.
 
  A statistics teacher wants to know how students in her school feel about mathematics courses. She decides to administer a survey to a random sample of students taking a mathematics course.
 
  She has several sampling plans to choose from.
  a. There are four ranks of students taking the class: freshmen, sophomores, juniors, and seniors. Randomly select 15 students from each class rank.
  b. Randomly select ten math class sections and survey every student in each of those sections.
  c. Each student has a nine-digit student number. Randomly choose 60 different nine-digit numbers and survey the students that correspond to those numbers.
  d. Randomly select a number from 1 to 5. Using the class roster, start at that number, then select every fifth student from the list after that.

[morrie123456]

Answer to Question 1

D

Answer to Question 2

Trial 1 required 8 families, Trial 2 required 11, and Trial 3 required 11. The mean of these is 10. So our estimate of the number of families needed to get 20 children is ten.

[newyorker26]

Excellent

[ecabral0]

Gracias!