Statistics - Confidence Interval
Not what you're looking for?
1.
a) A random sample of 100 managers in Alaska had an average yearly income of $125,500 with a standard deviation of $20,000. Develop the 95%, 90%, and 99% confidence intervals for the yearly income of all managers in Alaska.
b) If we assume we know the standard deviation of yearly income of all managers in Alaska is $25,000, build the 95%, 90%, and 99% confidence intervals for the average yearly income of all managers in Alaska.
2) The IQ scores of a population of students have mean 100 and standard deviation 15. If a sample of 100 students is selected, find the probability that sample mean of their IQ scores will lie between 95 and 130. If the sample size increases to 200 students, what is the corresponding probability?
3. True or False: A sample of 200 elements from a population with a known standard deviation is selected. For an interval estimation, the proper distribution to use should be a t distribution with 199 degrees of freedom (True or False)
Purchase this Solution
Solution Summary
The confidence intervals for a random sample is examined. Neat, step-by-step solutions are provided.
Purchase this Solution
Free BrainMass Quizzes
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.
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.