Probability Problem Set: Personal Website Hits and Email Use
Not what you're looking for?
1. Hits on a personal web site occur quite infrequently. They occur randomly and independently with an average of five per week.
a) Find the probability that the site gets 10 or more hits per week.
b) Determine the probability that the site gets 20 or more hits in two weeks
2. The random variable X is exponentially distributed with sigma = .5. Find the following probabilities.
a) P(X > 1)
b) P(X > .4)
c) P(X < .5)
d) P(X < 2)
3. A factory's worker productivity is normally distributed. One worker (worker 1) produces an average of 75 units per day with a standard deviation of 20. Another worker (worker 2) produces at an average rate of 65 per day with a standard deviation of 21. What is the probability that during one week (5 working days) worker 1 will produce more than worker 2?
4. According to TNS Intersearch, 69% of wireless web users use it primarily for receiving and sending e-mail. Suppose that three wireless web users are selected at random. What is the probability that all of them use it primarily for e-mail?
5.The effects of an antidepressant drug varies from person to person. Suppose that the drug is effective on 89% of women and 65% of men. It is known that 66% of the people who take the drug are women. What is the probability that the drug is effective?
Purchase this Solution
Solution Summary
This solution provides work and answers in plain text regarding a personal website hits and email use in the attached Excel file. Excel formulas are used and provided for calculations.
Solution Preview
See the attached file.
1. a. P (x>=10)=1- POISSON.DIST(9,5,TRUE)=1- 0.968172= 0.031828
b. there are more possibilities: 2*(P(x=0)*P(x>=20)+P(x=1)*P(x>=19)+P(x=2)*P(x>=18)+...+P(x=20)*P(x>=0))= 0.006907997
2. a) ...
Purchase this Solution
Free BrainMass Quizzes
Measures of Central Tendency
This quiz evaluates the students understanding of the measures of central tendency seen in statistics. This quiz is specifically designed to incorporate the measures of central tendency as they relate to psychological research.
Terms and Definitions for Statistics
This quiz covers basic terms and definitions of statistics.
Know Your Statistical Concepts
Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.
Measures of Central Tendency
Tests knowledge of the three main measures of central tendency, including some simple calculation questions.