# Statistics

### Statistics Guide: A normal population has a mean of 19 and a standard deviation of 5.

In this tutorial, we are going to use excel to calculate a z value from a know mean and standard deviation. Student Question: A normal population has a mean of 19 and a standard deviation of 5. Compute the z value associated with 25 To find the z-value at 25, we calculate (25 [...]Read more

### Statistics Guide: Customers experiencing technical difficulty with their internet cable hookup may call an 800 number for technical support

Student Question: Customers experiencing technical difficulty with their internet cable hookup may call an 800 number for technical support. It takes the technician between 150 seconds and 12 minutes to resolve the problem. The distribution of this support time follows the [...]Read more

### Statistics Guide: Solving the January Theory Stock Market Problem

Student Question: According to the “January theory” if the stock market is up for the month of January, it will be up for the year. If it is down in January,it will be down for the year. According to an article in The Wall Street Journal, this theory held for 28 out [...]Read more

### Statistics Guide: Internal Revenue Service is Studying Charitable Contributions

This tutorial requires Microsoft EXCEL for the computation of various statistical value. In order to follow along, please make sure you have a spreadsheet ready to go. Student Question: The Internal Revenue Service is studying the category of charitable contributions. A sample of [...]Read more

### Statistics Guide: The manufacturer of a laser printer reports the mean number of pages a cartridge will print before it needs replacing is 12,350

The following tutorial will setup this problem in excel. Use the template below to follow along and solve this problem for any data set. Student Question: The manufacturer of a laser printer reports the mean number of pages a cartridge will print before it needs replacing is [...]Read more

### Statistics Guide: Director of admissions at Kinzua University in Nova Scotia

Student Question: The director of admissions at Kinzua University in Nova Scotia estimated the distribution of student admissions for the fall semester on the basis of past experience. We are going to solve this problem using Microsoft Excel. First, take all of the data in the [...]Read more

### QNT 275 Final Exam Section 1 – Variable to Predict another Variable

What is the name of the variable that’s used to predict another variable? Explanatory Explanation: An explanatory variable, sometimes called a predictor, is a special type of independent variable that is used to measure another variable. An example of this an action is a study [...]Read more

### QNT 275 Final Exam Section 2 – Item Most Influenced by Outliers

Which of the following is most influenced by outliers? Mean Explanation: The mean will be the most affected from a single ore small number of outliers. For this reason, the mean is usually not the best measure of central tendency when the distribution is skewed or not [...]Read more

### QNT 275 Final Exam Section 3 – Continuous Random Variable

Which of the following can be represented by a continuous random variable? The average temperature in Tampa, Florida, during the month of July Explanation: A continuous random variable can take an infinitely large range of values. The average temperature can accept any value [...]Read more

### QNT 275 Final Exam Section 4 – Stratified Random Sample

Which of the following meets the requirements of a stratified random sample? A population contains 10 members under the age of 25 and 20 members over the age of 25. The sample will include two people chosen at random under the age of 25 and four people chosen at random over 25. [...]Read more