Distinguish between a sample and a population Define inferential statistics Distinguish between simple random sampling and stratified sampling Distinguish between random sampling and random assignment Populations and samples In statistics, we often rely on a sample that is, a small subset of a larger set of data to draw inferences about the larger set.
For example, finding the median is simply discovering what number falls in the middle of a set. The following numbers would be 27, 54, 13, 81, and 6. When you rearrange this data set, the order of the numbers becomes 6, 13, 27, 54, and Now the median number is 27 and not Another important thing to remember about the median is when you have an even number in your data set.
When the set is even, you take the two numbers that sit in the middle, add them together and then divide them by two. Your result is the answer. Notice that some of the numbers repeat. In this instance, 53 is the mode since it appears 3 times in the data set, which is more than any of the other numbers.
A key factor to remember about data sets is that they should always be placed in order. Finding the mode was pretty simple in this instance, but if the numbers were scrambled like before things would be a lot more difficult. The final part of descriptive statistics that you will learn about is finding the mean or the average.
The average is the addition of all the numbers in the data set and then having those numbers divided by the number of numbers within that set. Now in this data set there are 8 numbers.
The first thing we will do is add together all of the numbers within the set. You should have gotten Descriptive writing is a writing style which is used to describe in sensory detail the different things, places, people, and ideas. Descriptive writing sketches an image on the reader’s mind by giving a detailed description of the particular topic or subject.
Jun 13, · Sign in to report inappropriate content. Sample and Population Practice Statistics Problems Introduction to Descriptive Statistics - Duration: Sandra Webster 31, The sample mean height of the males is larger than the sample mean height of the females, while the sample standard deviation of the females is larger than the sample standard deviation of the males.
Both histo- grams are approximately symmetric. Student Guide: Discovery Projects in Statistics 3 Example 2 “I wonder if people who are bigger perfectionists also tend to have more anxiety.” This statement describes two different characteristics people may have—level.
Sample Problems Descriptive Statistics 1. 15, 18, 21, 22, 26, 28, 31, 39 (Population) a. Mean- b. Median- c.
Sum of squares- d. Variance- e. Standard deviation- f. Convert the raw scores of 15 and 39 to standard scores. g. Convert the raw scores of 15 and 39 to percentile scores.
Descriptive statistics describes data (for example, a chart or graph) and inferential statistics allows you to make predictions (“inferences”) from that data. With inferential statistics, you take data from samples and make generalizations about a population.