Purchase Solution

Calculating Expected Value and Descriptive Statistics

Not what you're looking for?

Ask Custom Question

1. A government has specialist who analyze the frequencies of letters of the alphabet in an attempt to decipher intercepted messages. In standard English text, a particular letter used at a rate of 6.8%.

a) Find the mean and standard deviation for the number of times this letter will be found on a typical page of 2000 characters.

b) In an intercepted message, a page of 2000 characters is found to have the letter occurring 155 times. Is this unusual?

2. Assume that a procedure yields a binomial distribution with n trails and the probability of success for one trail is p. Use the given values of n and p to find the mean and standard deviation. Also use the range rule of thumb to find the minimum usual value µ-2σ and the maximum usual value µ+2σ.

N=1435, p=1/5
µ=___
σ=____(round to one decimal place if needed)
µ-2σ=___ (round to one decimal place if needed)
µ+2σ=____(round to one decimal place if needed)

3. An insurance company charges a 21 year year old male a premium of $250 for a one year $50,000 life insurance policy. A 21 year old male has a 0.9985 probability of living for a year.

a) From the perspective of a 21 year old male (or his estate) what are the values of the two different outcomes? If he lives is____dollars If he dies is____dollars

b) What is the expected value for a 21 year old male who buys the insurance? Expected value____dollars

c) What would be the cost of the insurance if the company just breaks even ( in the long run with many such policies) instead of making a profit?____dollars

Purchase this Solution

Solution Summary

The solution gived detailed steps on solving some questions on the topic of descriptive statistics. All formula and calculations are shown and explained.

Solution Preview

1. A government has specialist who analyze the frequencies of letters of the alphabet in an attempt to decipher intercepted messages. In standard English text, a particular letter used at a rate of 6.8%.
a) Find the mean and standard deviation for the number of times this letter will be found on a typical page of 2000 characters.

Mean=2000*6.8%=136, and sd=sqrt(2000*6.8%*93.2%)=11.2584

b) In an intercepted message, a page of 2000 characters is found to have the letter occurring 155 times. Is this ...

Purchase this Solution


Free BrainMass Quizzes
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.

Terms and Definitions for Statistics

This quiz covers basic terms and definitions of statistics.

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.