|STAT 13 (1a, 1b, 1c)
Introduction to Statistical
Methods for the Life and Health Science
|Department of Statistics
Instructor: Ivo Dinov
|Due Date: Friday, Oct. 29, 2004
(HW_3_1) A manufacturer of disk drives for a well-known brand of
computers expects 4% of the drives to malfunction during the
computers warranty period. Let X
be the number of disk drives, in a batch of 11 randomly
selected disk drives, which malfunction during this period. X has a Binomial distribution.
- Identify n and p, the parameters of the Binomial
- In the context of this exercise, state the assumptions
required for X to have a Binomial distribution.
- Are the Binomial assumptions satisfied here?
- Calculate the probability that:
- No disk drive will malfunction during the warranty period.
- Exactly two disk drive will malfunction during the warranty
- At least three disk drives will malfunction during the
- Between 2 and 5 (inclusive) disk drives will malfunction
during the warranty period.
(HW_3_2) Assume the distribution of human blood types in one
region is: 29% type A; 12% type B; 48% type O and;
11% type AB. Suppose we
select one married couple at random, with the husband and the wife
this blood type distribution.
- If the wife has type B blood, what is the probability that the
husband has blood type B?
- What is the probability that both husband and wife have type A blood?
- What is the probability that at least one of them has blood
- What is the probability that they have the same blood type?
- (HW_3_3) In the following table members of a health club
are classified by gender and number of days per week they exercise.
|Gender \ Days of
What is the probability that a randomly selected health club member:
- is a female?
- is a female and exercises 4-5 times a week?
- is a male or exercises 4 or more times a week?